Changing Contract Terms in Australia: Legal Best Practices

In business, change is inevitable. Whether you’re scaling up, adjusting to regulation, or responding to unexpected events, you may need to alter an existing contract. But changing contract terms isn’t as simple as crossing out a few lines or sending a quick email - doing it the wrong way can cause confusion, disputes, or even make the contract unenforceable.

This guide explains how contract changes (variations) work under Australian law, how to do them properly, and how to avoid common legal pitfalls.

What Is A Contract Change?

A contract change (or variation or amendment) occurs when the parties agree to alter one or more terms of an existing contract. Examples include:

• Adjusting prices or payment terms

• Changing delivery dates or project milestones

• Adding or removing services or products

• Introducing new clauses, such as confidentiality or exclusivity

• Modifying the scope of work under a Service Agreement

A variation updates an existing contract rather than replacing it. It must comply with the law and - unless the contract provides otherwise - requires the agreement of all parties.

Why Change A Contract?

You might need a change because:

• Market or regulatory shifts affect pricing or performance

• You’re expanding supply, reducing volumes, or changing deliverables

• Force majeure or supply chain issues require flexibility

• You’ve discovered unclear or unfair clauses that need clarification

Whatever the reason, the process matters. Poorly handled variations are a leading cause of contractual disputes.

Can You Change A Contract At Any Time?

Only by agreement - and only if the contract or law allows it. Under Australian contract law:

• Mutual consent is required. You can’t vary a contract unilaterally unless it expressly allows you to do so (for example, a price-adjustment clause).

• Many contracts contain a variation clause, usually requiring changes to be in writing and signed by all parties. Ignoring this makes a change unenforceable.

• Certain contracts (for example, land transactions or leases) must be varied in writing to comply with statute.

• If changes are so fundamental that they alter the contract’s core purpose, you may need to terminate and re-enter a new agreement.

Beware of the Unfair Contract Terms Regime

Under the Australian Consumer Law (ACL) and ASIC Act, the unfair contract terms regime now applies broadly to standard form contracts with small businesses or consumers.

From 9 November 2023, unilateral variation clauses (where one party can change terms without consent) are a key enforcement focus. A variation clause is likely unfair if it allows one party - usually the stronger one - to change important rights, prices or obligations without providing notice or a right to terminate.

If you rely on such a clause, make sure it’s transparent, proportionate, and includes reasonable notice and exit options.

The Legal Process For Changing A Contract

1. Review The Existing Contract

Look for any clause titled Variation, Amendment, or Entire Agreement. It will usually state:

• whether changes must be written,

• who can authorise them, and

• how they take effect.

If unclear, get a lawyer to review the contract - especially for high-value or complex arrangements.

2. Negotiate And Document The Change

Discuss the change and its implications with all parties. Then document it clearly. The main options are:

• Amending Agreement - a short document describing each change and referring to the original contract.

• Deed of Variation - used when no new consideration is provided (e.g. one party agrees to extend time or waive payment).

• Restated Contract - where extensive changes make redrafting simpler than amending piecemeal.

Avoid relying on informal emails for anything beyond minor operational tweaks.

3. Ensure Proper Execution

All affected parties must sign or otherwise clearly consent to the change.

• Electronic signatures are valid in most cases under the Electronic Transactions Acts (Cth and states/territories), unless excluded by the contract or the nature of the document.

• Deeds require stricter execution. Some jurisdictions still expect physical signatures and witnessing for individuals; companies can execute electronically if they meet Corporations Act s127 conditions (and most now do after the 2022 reforms).

Check the governing law and your execution clause before signing electronically.

4. Circulate And Store Updated Copies

After signing, share copies with all parties and store the updated version securely. If the contract is registered (for example, a franchise or lease), check whether the variation also needs registration or notice to regulators.

Best Practices For Contract Changes

• Put it in writing - even if not required. Oral variations are hard to prove.

• Be precise - refer to exact clause numbers and wording being changed.

• Use the right document type - amendment, deed, or restated agreement.

• Review flow-on effects - pricing changes, termination rights, linked agreements or regulatory obligations.

• Maintain a clean record - keep all drafts, correspondence and the final consolidated contract.

Common Legal Pitfalls

• Unilateral changes without consent - can amount to repudiation.

• Vague language - creates conflicting terms and uncertainty.

• Ignoring procedure - failure to comply with a “written and signed” clause invalidates the variation.

• Triggering hidden obligations - for example, shareholder approvals or third-party consent clauses.

• Failing to consider the unfair contract terms regime - especially for small business clients or contractors.

Key Legal Documents

• Deed of Variation - formal, often used when no fresh consideration exists.

• Amending Agreement - practical for clear, mutual changes supported by consideration.

• Updated Contract (Restated) - for extensive revisions.

• Board or Shareholder Resolution - where company constitutions require authorisation for major contractual amendments.

Broader Legal Implications

Contract variations can ripple across other compliance areas:

• Consumer Law: changes to pricing or performance may alter ACL obligations or require updated disclosures.

• Employment: variations to employment contracts must comply with the Fair Work Act and relevant awards - consent is crucial.

• Privacy: if data handling terms change, update your Privacy Policy and notify affected individuals if required.

• Franchising: follow the Franchising Code of Conduct variation procedures, including disclosure obligations.

When To Seek Legal Help

Get advice if:

• the change is high-value, complex, or touches multiple agreements

• no variation clause exists

• you’re uncertain whether the change needs to be a deed

• one party refuses to sign or insists on unilateral rights

• the contract involves government, franchise, or cross-border parties

Even short legal input can ensure clarity and enforceability.

Key Takeaways

• Contract changes must be agreed by all parties and usually in writing.

• Check the existing variation clause and follow it exactly.

• Beware unilateral variation clauses - they can breach the unfair contract terms regime.

• Deeds and electronic execution have distinct requirements - confirm before signing.

• Keep full records and monitor the wider legal effects of any change.

• Seek advice for high-value, high-risk, or multi-party variations.

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If you’d like help drafting a Deed of Variation or reviewing a proposed contract change, contact Sprintlaw on 1800 730 617 or team@sprintlaw.com.au for a free, no-obligations chat.