Quick answer: An employment contract variation letter should identify the existing contract, explain the proposed change, state when it starts and confirm whether the employee accepts it. Employers should use it for changes such as duties, hours, location, pay structure or reporting lines, while checking the Fair Work Act 2009, the National Employment Standards (NES), any Modern Award and the original contract first.

The safest approach is to give the employee a clear written proposal, allow a reasonable opportunity to consider it and keep evidence of agreement. A variation letter should not be used to remove minimum entitlements, disguise a termination or impose a substantial change without proper process.

What is an employment contract variation letter?

An employment contract variation letter is a written record that changes one or more agreed employment terms. It should be read with the original employment contract rather than replacing the entire agreement unless the parties intentionally sign a new contract. The letter should make it easy to see what stays the same and exactly what changes.

Common variations include a promotion, revised duties, a change from full-time to part-time work, a new work location, a salary review, a change to commission arrangements or an agreed flexible work pattern. Some changes can be administrative; others may affect the employee’s classification, award coverage, hours, pay or job security and need closer review.

What should an employment contract variation letter include?

Avoid phrases such as “all other conditions remain unchanged” if the change affects related terms. For example, changing hours may affect leave accrual, rostering, award provisions or part-time written hours. Spell out the practical consequences so payroll and managers apply the variation consistently.

When can an employer vary an employment contract?

An employer can propose a variation where the employee agrees, the original contract permits the change, or the change is otherwise authorised by law or an applicable industrial instrument. Agreement should be genuine and informed. A manager should explain the business reason, the proposed effect and the employee’s opportunity to ask questions before the change is implemented.

Employers should be particularly careful with unilateral changes to pay, guaranteed hours, duties, location or status. A purported variation that leaves an employee worse off than the NES or applicable award may be ineffective and expose the business to underpayment or other claims. The Fair Work Ombudsman employment contract guidance is a useful starting point, and employers can review the Fair Work Act 2009 for the governing legislation.

How to write and implement the variation

1. Check the existing agreement and legal minimums

Read the original contract, relevant policies, award or enterprise agreement and any prior variation. Confirm the employee’s classification and current pay. Test the proposed change against ordinary hours, overtime, weekend work, public holidays, leave, allowances and superannuation where relevant.

2. Explain the reason and the practical impact

Use plain language. If duties are changing, list the new responsibilities and reporting line. If hours are changing, state the new ordinary hours, days and notice arrangements. If the change is temporary, give an end date or review date. A vague letter creates avoidable disputes because each person remembers a different conversation.

3. Give reasonable time to consider it

Provide the letter before the change starts wherever possible. Give the employee a reasonable chance to obtain advice, raise concerns and propose alternatives. Do not pressure the employee to sign immediately or present a major change as a routine administrative update.

4. Record acceptance and update payroll

Keep the signed letter or reliable written acceptance with the original contract. Send the final version to payroll and the relevant manager, update the HR record and diarise any review date. Check the first payslip after implementation against the new terms and applicable minimums.

Contract variation risks for employers

The most common mistake is changing a headline term without checking connected obligations. A salary change may alter overtime assumptions; a new location may trigger travel or consultation issues; a reduction in hours may affect part-time arrangements; and new duties may require a different award classification. The variation letter should be supported by a short internal checklist showing that these issues were considered.

Do not use a variation letter to retrospectively approve an underpayment or to make an unlawful deduction. Do not backdate it merely to tidy up an old verbal arrangement. If the business and employee agreed a change earlier, record the actual history accurately and obtain advice about any gap.

Employers can use general employment documents for related HR paperwork, review employment contract guidance before changing core terms, and access employment agreement templates when a new agreement is more suitable than a short variation.

Variation letter checklist

1. Identify the original contract and clause being changed.
2. Describe the old and new terms without ambiguity.
3. Check the NES, Modern Award, enterprise agreement and minimum pay.
4. State the commencement date, duration and any review date.
5. Explain the practical impact on duties, hours, pay, leave or location.
6. Give the employee time to consider the proposal and document acceptance.
7. Update payroll, HR records and the manager’s instructions.

When should an employer get advice?

Get advice before issuing the letter if the proposed change reduces pay or guaranteed hours, moves the employee to a different classification, changes employment status, relocates the employee, affects a protected workplace right or follows a performance or misconduct process. Early review can identify whether consultation, a new agreement or a different process is required.

A clear variation letter protects the employer by creating a shared record, but it cannot override the Fair Work Act 2009 or an applicable award. Use the document as one part of a disciplined process: check the legal minimums, explain the proposal, obtain informed agreement and verify the first payroll outcome.

How to explain a variation to managers and payroll

Once the employee accepts, do not rely on the letter sitting in a personnel file. Send a short implementation note to the manager and payroll team that identifies the effective date, approved hours, rate and any restrictions. Managers should know which terms are contractual and which are controlled by the award, because an informal promise made during rostering can create confusion later.

For a temporary variation, set a review date and explain what happens at the end of the period. For a promotion or permanent change, update the position description and reporting structure. If the change affects access to systems, company equipment, confidentiality or delegated authority, make sure the relevant policy and induction steps are updated at the same time.

A second check after the first pay cycle is worthwhile. Compare the payslip, timesheet and roster with the signed variation. Correct errors promptly, keep a note of the correction and avoid asking the employee to sign a new document simply to hide an earlier mistake.