Overview of the General Rules on Amendment of Construction Contracts under the Law on Construction No. 143/2025/QH15 and Decree No. 210/2026/ND-CP
The Law on Construction No. 143/2025/QH15 (“Law on Construction 2025″ or “LOC 2025“) was passed by the National Assembly on 25 June 2025 and took effect on 1 July 2025, replacing the Law on Construction No. 50/2014/QH13 (as amended and supplemented). To provide detailed guidance for the implementation of the Law on Construction 2025, the Government promulgated Decree No. 210/2026/ND-CP dated 18 July 2026 on construction contracts (“Decree 210“), which took effect on the date of its issuance.
In addition to amending and supplementing numerous specific provisions relating to construction contracts, the Law on Construction 2025 and Decree 210 also reflect a significant shift in the legislative approach to the performance of construction contracts. While the previous legal framework primarily focused on contract administration, the new regulations have gradually adopted a contract governance approach, emphasising risk management, clearly allocating responsibilities among relevant parties, enhancing proactiveness during contract performance, and strengthening project governance.
Against this background, the provisions governing the amendment of construction contracts have not only been refined from a legislative drafting perspective but have also become an important mechanism for ensuring contractual flexibility while maintaining control over contract amendments throughout project implementation.
This article marks the beginning of BFSC Law LLC’s series of publications on construction contracts and public-private partnership investment project contracts (PPP project contracts). Within the scope of this article, we focus on providing an overview of the general rules governing the amendment of construction contracts under the Law on Construction 2025 and Decree 210, with particular emphasis on the provisions applicable to construction contracts for public investment projects and PPP projects. More in-depth topics, including contract price adjustment, adjustment of the contract implementation schedule, adjustment of the scope and quantity of work, extension of the contract implementation period, as well as legal issues relating to PPP project contracts, will be analysed by BFSC Law LLC in subsequent articles of this publication series.
(1) Concept of Amendment of Construction Contracts
The Law on Construction 2025 and Decree 210 do not provide a definition of “amendment of a construction contract”.
However, based on the provisions of the Law on Construction 2025 and Decree 210, the amendment of a construction contract may be understood to include:
- the adjustment of an executed construction contract; and/or
- the addition of one or more provisions to an executed construction contract.
Accordingly, under the new legal framework, the amendment of a construction contract is not limited to the adjustment of existing contractual provisions but also includes the addition of new provisions to an executed contract during its performance.
(2) Matters That May Be Amended in a Construction Contract
The Law on Construction 2025 and Decree 210 continue to recognise the principle that the parties are entitled to amend a construction contract during its performance. However, such amendments may only be made in respect of matters permitted by law and must satisfy all applicable statutory requirements.
Accordingly, the parties may agree to amend one or more of the following matters:
- the scope of work;
- the quantity of work;
- the contract price;
- the contract implementation schedule;
- the contract implementation period;
- the rights and obligations of the parties; and
- other matters as agreed by the parties, provided that such agreement complies with applicable laws.
It can be seen that the scope of contractual amendments under the Law on Construction 2025 and Decree 210 is relatively broad, allowing the parties to adjust most contractual provisions during contract performance. However, this right of amendment is not absolute and must be exercised in compliance with the conditions, procedures and approval authority prescribed by the Law on Construction 2025, Decree 210 and other relevant laws.
For certain significant matters, such as the adjustment of the contract price, adjustment of the contract implementation schedule, adjustment of the quantity of work, extension of the contract implementation period, or changes to the scope of work under construction contracts for public investment projects and PPP projects, the law further prescribes specific conditions and stricter control mechanisms to ensure that contractual amendments do not alter the investment objectives, exceed the investment decision-making authority, or give rise to the abuse of contract amendments during project implementation. These issues will be analysed in greater detail by BFSC Law LLC in the subsequent articles of this publication series.
(3) Circumstances in Which a Construction Contract May Be Amended
Article 84.2 of the Law on Construction 2025 provides that the parties to a construction contract may agree to amend the construction contract in the following circumstances:
(i) the State introduces changes to policies or laws that directly affect the performance of the construction contract;
(ii) there is any change or adjustment to the requirements relating to the contents or scope of work, technical requirements, product quality, implementation schedule, advance payment conditions or payment conditions as agreed by the parties in the construction contract;
(iii) a force majeure event occurs in accordance with Article 13.1 of the Law on Construction 2025;
(iv) there is a fundamental change of circumstances in the performance of the contract in accordance with Article 13.2 of the Law on Construction 2025; or
(v) other circumstances as agreed by the parties, provided that such agreement complies with the Law on Construction 2025 and other relevant laws.
It can be seen that the Law on Construction 2025 continues to uphold the principle of respecting the parties’ freedom of contract in relation to the amendment of construction contracts. However, contractual amendments may only be made in circumstances permitted by law or as agreed by the parties, provided that the agreed amendments comply with the Law on Construction 2025 and other relevant laws.
(4) Prerequisites for the Amendment of a Construction Contract
Construction contractors should pay particular attention to the fact that, under the Law on Construction 2025 and Decree 210, except in cases involving a force majeure event or a fundamental change of circumstances, the construction contract must contain specific provisions on the following matters in order for the contractual amendment mechanism to be invoked:
- matters that may be amended;
- the scope of contractual amendments;
- the circumstances in which the contract may be amended; and
- the procedures for contract amendment.
In other words, for most circumstances in which a construction contract may be amended, the availability of the amendment mechanism depends primarily on the contractual provisions governing contract amendment that have been agreed by the parties.
Another noteworthy point is that Article 95.7 of the Law on Construction 2025 establishes transitional provisions for construction contracts executed before 1 July 2026. Accordingly, where a force majeure event or a fundamental change of circumstances as prescribed in Article 13 of the Law on Construction 2025 occurs, the parties are entitled to apply the provisions of the Law on Construction 2025 to address such circumstances, including the right to request an amendment of the contract under Article 84.
However, it should be noted that this transitional provision should not be construed as excluding the parties’ right to rely on other applicable provisions of civil law in respect of construction contracts executed before 1 July 2026 where a force majeure event or a fundamental change of circumstances occurs. In other words, the parties remain entitled to apply the relevant provisions of civil law to resolve disputes or deal with the consequences of a force majeure event or a fundamental change of circumstances. The provisions of the Law on Construction 2025 may only be applied to the extent permitted under Article 95.7 or where the relevant provisions of civil law are identical or substantially similar to those of the Law on Construction 2025.
(5) Rules on the Amendment of Construction Contracts for Public Investment Projects and PPP Projects
For construction contracts relating to public investment projects and public-private partnership (“PPP”) projects, in addition to the general rules governing contract amendments, the Law on Construction 2025 and Decree 210 also prescribe specific provisions on the authority to approve contract amendments, the scope of amendments, the conditions for amendments, and the applicable procedures.
5.1. Authority of the Employer to Amend the Contract
Pursuant to Article 84.3 of the Law on Construction 2025 and Article 23.3 of Decree 210, the Employer is entitled to decide on the amendment of a construction contract in the following circumstances:
(i) where the amendment does not extend beyond the project implementation period as approved or subsequently adjusted;
(ii) where the amendment may result in the contract value exceeding the approved procurement package value (including contingencies) but does not exceed the approved or adjusted total investment capital;
(iii) where a force majeure event or a fundamental change of circumstances occurs, the Employer may consider and decide on contract amendments, provided that such amendments:
- do not change the investment objectives;
- do not alter the project scale;
- do not exceed the approved or adjusted total investment capital;
- ensure the investment efficiency of the project; and
- prevent loss and waste.
(iv) In the event of force majeure or a fundamental change of circumstances, the amendment may include:
- the contract type;
- the contract pricing mechanism;
- the method of price adjustment;
- the source of data used for contract price adjustment; and
- other related contractual matters,
provided that such amendments remain within the authority specified in items (i) and (ii) above.
5.2. Circumstances Requiring Approval by the Investment Decision-Making Authority or Requiring Procurement Procedures
In addition to the Employer’s authority referred to in Section 5.1 above, certain contract amendments must be submitted to the competent investment decision-making authority for approval and, in some cases, may require contractor selection procedures in accordance with the procurement laws, including:
- where the investment project or the total investment capital must be adjusted; or
- where additional reasonable quantities or works arise for which no contract rates exist, and the parties fail to reach agreement on the applicable unit rates, prices, quantities, payment arrangements, or other matters necessary for amending the contract.
5.3. Adjustment of Quantities and Scope of Work
Article 23 of Decree 210 provides that the adjustment of quantities or scope of work depends on the type of construction contract.
(a) Lump Sum Contracts
For lump sum contracts, quantities or scope of work may be adjusted where:
- reasonable increases or decreases in quantities or scope of work arise from adjustments to the contractual scope of work at the Employer’s request or at the Contractor’s proposal as approved by the Employer; or
- a force majeure event or a fundamental change of circumstances occurs in accordance with Article 13.1 and Article 13.2 of the Law on Construction 2025.
(b) Fixed Unit Price Contracts and Adjustable Unit Price Contracts
For fixed unit price contracts and adjustable unit price contracts, quantities or scope of work may be adjusted where:
- the actual certified quantities increase or decrease compared with the quantities specified in the contract for work items already having agreed unit rates; or
- additional reasonable quantities or work arise for which no unit rates are provided in the contract, and the parties have agreed on supplementary unit rates through a contract amendment.
(c) Adjustment Among Joint Venture Members
Where quantities or scope of work are reallocated among members of a contractor joint venture without changing the contract price, the Employer may approve such adjustment based on:
- the unanimous agreement of the joint venture members;
- the qualifications and experience of each member; and
- the requirement to ensure safety, quality, efficiency, and compliance with the contractual implementation period and schedule.
5.4. Adjustment of Contract Prices and Unit Rates
5.4.1. Principles for Adjustment of Contract Unit Rates
Under Decree 210, any adjustment of contract unit rates or contract prices must simultaneously satisfy the following conditions:
(i) unit rate adjustment is only applicable to adjustable unit price contracts, time-based contracts, hybrid contracts, and other construction contracts for which unit rate adjustment is permitted by law;
(ii) contract unit rates shall be adjusted in accordance with the scope, contents, methodology, and adjustment basis agreed by the parties in the contract and in compliance with applicable laws; and
(iii) unit rate adjustment shall apply only to work quantities for which the parties had agreed, at the time of contract execution, that unit rate adjustment would be permitted.
5.4.2. Circumstances for Adjustment of Contract Unit Rates and Contract Prices
(a) Actual Quantities Increase or Decrease by More Than 20%
Where the actual quantity of work increases or decreases by more than 20% compared with the corresponding contractual quantity, and such increase or decrease simultaneously results in:
- a change exceeding 0.25% of the contract price; and
- a change exceeding 1% of the unit rate for the relevant work item,
the parties shall agree on a new unit rate in accordance with the principles specified in the contract.
The new unit rate shall apply:
- to the portion of actual quantities exceeding 120% of the contractual quantities; or
- to the entire certified quantity where the actual quantity decreases by more than 20%.
(b) Actual Quantities Increase or Decrease by No More Than 20%
Where the actual quantity of work increases or decreases by no more than 20% compared with the contractual quantity, payment shall be made based on the contract unit rates, including any unit rates previously adjusted in accordance with the contract.
(c) Additional Work Without Agreed Unit Rates
Where additional quantities or work arise for which no unit rates are provided in the contract, the parties shall agree on new unit rates in accordance with the contractual principles for the purpose of payment.
If the parties fail to agree on the applicable unit rates or other matters necessary for amending the contract, procurement procedures for selecting a contractor to perform the additional work may be required.
5.4.3. Methods for Adjusting Contract Unit Rates and Contract Prices
Under Decree 210, contract unit rates and contract prices may be adjusted using either of the following methods:
- the direct compensation method; or
- the price adjustment coefficient (Pn) method prescribed in the Appendix to Decree 210.
A construction contract may combine both methods.
Where the price adjustment coefficient (Pn) does not apply to the entire contract, the parties shall agree on the formula for determining Pn for each:
- work item;
- group or category of work; or
- specific cost component.
5.4.4. Sources of Price Information and Price Indices
Under Decree 210, the sources of price information, price indices, and the contract price adjustment methodology must:
- correspond to the nature and contents of the work;
- correspond to the cost structure;
- correspond to the applicable pricing mechanism; and
- be specifically agreed and provided for in the contract.
Where construction price databases or construction price indices published by the Ministry of Construction or the Provincial People’s Committee are unavailable or inappropriate, the Employer may:
- determine the applicable prices or construction price indices in accordance with the laws on construction investment cost management; or
- refer to prices or price indices published by the Ministry of Finance or other competent authorities.
For cost items incurred overseas, the parties may agree to use price information or price indices published by the competent authority or organisation in the jurisdiction where such costs arise.
5.4.5. Circumstances Where No Contract Amendment Document Is Required
Under Decree 210, where the mechanism for price adjustment has already been specifically agreed in the contract, the administration and payment of adjusted contract amounts do not require the execution of a formal contract amendment.
5.5. Adjustment of the Contract Implementation Period and Implementation Schedule
Pursuant to Article 25 of Decree 210, where an adjustment to the contract implementation period or implementation schedule results in the project implementation period being exceeded, the Employer must report to the investment decision-making authority for consideration and approval of the adjustment to the project implementation period before the parties agree on the adjustment to the contract implementation period or implementation schedule.
5.6. Procedures for Amendment of Construction Contracts
Pursuant to Article 22.4 of Decree 210, the amendment of construction contracts for public investment projects and PPP projects shall be carried out in the following sequence:
Step 1. Proposal for Contract Amendment
The party requesting the amendment shall submit a written proposal to the other party together with the relevant supporting documents (if any).
The proposal shall clearly specify:
- the legal basis for the proposed amendment;
- the grounds supporting the amendment;
- an assessment of the impact of the amendment on:
- the contract implementation period;
- the contract implementation schedule;
- the contract price;
- the quality of the contractual deliverables; and
- any other relevant matters.
Step 2. Response to the Proposal
Within 07 working days from the date of receipt of the proposal, the receiving party shall respond in writing.
Where the receiving party disagrees with the proposed amendment, it shall notify the proposing party in writing, clearly stating the reasons for its refusal.
Step 3. Negotiation and Execution of the Contract Amendment
The parties shall negotiate the proposed amendments and execute a written contract amendment as the basis for implementation.
Where the parties fail to reach agreement on the proposed amendment, the Employer shall organise the implementation of the relevant work in accordance with the procurement laws and other applicable laws.
(6) Practical Implications for Construction Contract Parties
The new provisions introduced under the Construction Law 2025 and Decree No. 210/2026/ND-CP demonstrate that construction contract amendment is no longer regarded merely as a mechanism for dealing with isolated issues arising during contract performance. Instead, it has become an essential contractual mechanism that should be considered from the contract negotiation, drafting and contract governance stages.
For employers (project owners), the new legal framework requires construction contracts to contain clear amendment mechanisms while ensuring that any contract amendment is approved by the appropriate authority, particularly for public investment projects and PPP projects. In many cases, contract amendments may affect the project implementation period, the approved total investment or procurement procedures. Accordingly, identifying the proper authority and complying with the prescribed procedures has become increasingly important in project administration.
For contractors, clearly drafted contractual provisions governing the circumstances, scope, procedures and process for contract amendment provide a more certain legal basis for requesting or negotiating amendments where issues arise during contract performance, particularly in relation to variations in work scope, quantities, contract rates, contract price, project schedule and completion period.
Overall, while the Construction Law 2025 and Decree No. 210/2026/ND-CP provide broader opportunities for contract amendment, they also introduce a more structured regulatory framework intended to ensure transparency, protect investment efficiency and reduce the risk of inappropriate or unjustified contract amendments during project implementation.
Publication Series on Construction Contracts and PPP Project Contracts
This article is the first publication in BFSC Law LLC’s series on construction contracts and public-private partnership investment project contracts (PPP project contracts).
In the forthcoming articles, BFSC Law LLC will provide in-depth analysis of the following topics, including:
- Rules governing the amendment of PPP project contracts;
- Rules on contract amendments under the standard construction contract forms issued together with Decision No. 1040/QD-BXD of the Ministry of Construction;
- Rules on the amendment of PPP project contracts under the current standard PPP contract forms;
- Adjustment of contract unit rates and contract prices;
- Adjustment of the contract implementation schedule and contract implementation period;
- Adjustment of the quantity and scope of work under construction contracts;
- Dispute resolution mechanisms for construction contracts and PPP project contracts.
This publication series is intended to provide updates on the latest legal developments while analysing and comparing the applicable legal framework with the standard construction contract forms and international practices, thereby assisting employers, contractors, consultants and other project participants in the governance of construction contracts and PPP project contracts.
Disclaimer
This article is intended solely for the purpose of providing general information on the applicable laws and regulations. It does not constitute legal advice for any specific matter.
The application of legal provisions depends on the specific facts and circumstances of each contract and each project. Readers are encouraged to seek advice from qualified lawyers or legal professionals before making any decision or taking any action based on the contents of this article.
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Author:
Phan Quang Chung
Founder & Managing Lawyer
BFSC Law LLC
Specialising in Construction Law • Infrastructure • PPP • FIDIC • Corporate, M&A • Capital Markets • Banking & Finance • Commercial Contracts