Australian employers often ask: can I require a medical certificate when an employee takes sick leave? The answer is yes — but the rules under the Fair Work Act 2009 set clear boundaries on when and how you can demand evidence, what forms are acceptable, and what happens if the employee refuses.

Under section 107 of the Fair Work Act, employers can require an employee to provide evidence that would satisfy a “reasonable person” of their entitlement to personal/carer’s leave. A medical certificate is the most common form, but a statutory declaration is equally valid. Employers cannot demand one specific type of evidence — and if the employee provides reasonable evidence, the employer must pay the leave and cannot unreasonably refuse the request. This guide covers the evidence rules, notice obligations, when you can withhold pay, and how the rules differ for casual employees.

What the Fair Work Act Says About Medical Certificates and Sick Leave

Section 97 of the Fair Work Act gives full-time employees 10 days of paid personal/carer’s leave per year (pro-rata for part-time employees). Section 107 sets the notice and evidence requirements that apply when an employee takes this leave.

The key rule for employers: you may require evidence that would satisfy a “reasonable person” of the entitlement to the leave. This means evidence that genuinely shows the employee was unwell or caring for an unwell family member. The Fair Work Ombudsman confirms that a medical certificate or a statutory declaration is typically sufficient — one is not required over the other.

Employers cannot unreasonably refuse to authorise an employee to take personal leave (s.107(4)). If the employee provides reasonable evidence and proper notice, the employer must pay the leave entitlement under the NES.

Notice Requirements: What Employees Must Tell Employers

Before an employer can assess whether a medical certificate is needed, the employee must first meet their notice obligations under s.107(1) and (2):

• Notify as soon as practicable: The employee must tell the employer they’re taking leave — this may be after the leave has started, but only where it was impracticable to give earlier notice.
• Advise the expected period: The employee must let the employer know how long they expect to be away, so the employer can plan accordingly.
• Provide evidence if requested: If the employer asks for evidence, the employee must provide it. The timeframe should be reasonable — typically within a few days of returning to work.

If an employee fails to give notice and doesn’t have a reasonable excuse, the employer may not be obligated to pay for the absence. However, employers should apply this cautiously — docked pay that is later found to be unreasonable can trigger a wages claim. For template leave policies, see our free employment documents.

Can Employers Demand a Medical Certificate Specifically?

No. Employers cannot insist on a medical certificate and reject a statutory declaration. The Fair Work Act requires evidence that would satisfy a “reasonable person” — not evidence in a specific format. This is a common misconception among employers.

If an employer demands a medical certificate and the employee provides a statutory declaration instead, the employer must accept it unless there’s a genuine reason to doubt its validity. Forcing an employee to obtain a paid medical appointment when a statutory declaration would suffice could be seen as unreasonable conduct.

In practice, most employers require a medical certificate for absences of three or more days and accept a statutory declaration for shorter periods. Some modern awards contain specific terms about evidence for short absences — always check the applicable award. For advice on structuring your HR best practice policies, consult our employer resources.

What Happens if an Employee Refuses to Provide Evidence?

If an employer requests evidence and the employee fails or refuses to provide it, the employer is not required to pay for the leave under s.107(3). However, this should be handled carefully:

• Communicate the requirement: Tell the employee clearly what evidence is needed and provide a reasonable deadline.
• Don’t dock pay retrospectively: If the employee has already been paid, recovering it through payroll deductions can breach the Fair Work Act.
• Consider the circumstances: An employee who is genuinely unwell but unable to obtain a medical certificate due to access or cost issues should not be penalised. Some employers cover the cost of the medical appointment if they require a certificate.

If the pattern of refusing to provide evidence is repeated, it may indicate a broader conduct issue rather than a one-off leave dispute. In that case, formal warnings under your general employment documents and performance management policies are appropriate.

Sick Leave Rules for Casual Employees

Casual employees are not entitled to paid personal/carer’s leave under the NES. They can, however, access two days of unpaid carer’s leave per occasion under s.96 of the Fair Work Act. The notice and evidence requirements in s.107 still apply — the employee must notify the employer and may be asked for evidence.

Casual employees who accept casual conversion to permanent employment become entitled to paid personal leave prospectively.

Employer Obligations Summary: Medical Certificates and Payroll

For employers managing sick leave and medical certificates, the key obligations are straightforward but strict:

• Accept either a medical certificate or a statutory declaration as valid evidence
• Give employees a reasonable timeframe to provide evidence
• Pay the leave if valid evidence and notice are provided
• Track leave accruals and personal leave balances accurately
• Apply your evidence policy consistently across all employees

Inconsistent application of medical certificate requirements — demanding certificates from some employees but not others — can lead to claims of adverse action or discrimination under the general protections provisions of the Fair Work Act. For employers who need help reviewing their leave and payroll policies, our payroll compliance advisory provides direct access to specialist employment lawyers.