Guide
Medical Certificate vs Statutory Declaration, What's the Difference?
14 Nov 2026
Guide
Do You Need a Medical Certificate for One Day Off Work?
Yes, employers can request evidence for a single day. Here is exactly when and what your rights are.
5 min readMedically reviewedAustralia-wide
An employer can request reasonable evidence for even one day of sick leave under Australian workplace rules, depending on the circumstances and workplace policy. A medical certificate is one common form of evidence. If you need one, a doctor must still assess your condition and decide whether certification for that day is clinically appropriate.
The Direct Answer
Yes, an employer can legally ask for a medical certificate even for a single day's absence. Under Section 107 of the Fair Work Act 2009, employers are entitled to request 'reasonable evidence' of personal leave for any duration, including one day. The key word is 'reasonable', whether it is reasonable to request a certificate for a single day depends on the circumstances.
What 'reasonable' means in practice
The Fair Work Commission has indicated that requiring a certificate for every single-day absence, without specific cause, can be unreasonable in some circumstances, particularly when accessing a GP on the same day is difficult or costly. However, if an employer has a documented policy, or if there is a pattern of suspicious absences (such as consistently on Mondays or Fridays), a single-day certificate request is more likely to be considered reasonable. Under the medical certificate rules in Australia, notice comes first: tell your employer as soon as possible.
When your enterprise agreement may set different rules
Many enterprise agreements and employment contracts specify when certificates are required, for example, only after two consecutive days, or only when a pattern of absences is identified. Check your specific enterprise agreement or contract. These provisions override the general Fair Work Act default if they are more generous.
Do You Need a Certificate for One Day Off, Permanent vs Casual Employees
| Full-time permanent | 10 days paid per year | The employer can request evidence for any absence, including 1 day, if reasonable |
| Part-time permanent | Pro-rata of 10 days | Same as full-time, pro-rata entitlement |
| Casual | No paid personal leave | The employer has limited grounds to require evidence without a specific contractual basis |
| Fixed term | Same as permanent | The same rules apply; personal leave accrues |
Can You Use a Statutory Declaration Instead of a Medical Certificate?
Yes. Under the Fair Work Act, 'reasonable evidence' does not have to be a medical certificate; it can also be a statutory declaration (a written statement made under oath before an authorised person). A statutory declaration is commonly used when a patient genuinely could not access a GP on the day. Most employers accept it, although some enterprise agreements specifically require a medical certificate or a doctor's note.
When a statutory declaration is a practical alternative
If you had a genuine one-day illness and could not access a GP, for example, on a weekend, public holiday, or in a regional area, a stat dec is often the practical solution. OMC Health is available 7 days a week, so a same-day online GP consultation is now a realistic option, even on Saturdays and Sundays.
How to Get a Same-Day Certificate for a One-Day Illness
Through OMC Health, a one-day sick leave certificate can be issued after a real-time phone consultation with a GP, if clinically appropriate. The process takes 5–15 minutes. If the GP determines a certificate is clinically appropriate, it is emailed to you the same day. This is particularly useful for single-day absences where you are unwell but not unwell enough to visit a clinic. Learning how to get a medical certificate online before you book saves time when the GP calls about that single day.
Book online, takes 3 minutes
Phone consultation, 5–15 minutes
Certificate emailed soon after the consult, if approved
Includes GP's AHPRA number and QR verification code
From $9.99, full refund if GP determines certificate not appropriate
See one day medical certificate which covers booking for a single day off work.
What If Your Employer Refuses Your Certificate?
A valid certificate from a registered GP can satisfy the Fair Work Act's 'reasonable evidence' requirement. An employer cannot unreasonably refuse it. If your employer refuses a valid certificate without legitimate grounds, you have the right to escalate. First, request written grounds for the refusal. If they are not legitimate, contact the Fair Work Ombudsman at fairwork.gov.au or on 13 13 94.
Get Started, Book a Consultation Today
If you need a medical certificate, OMC Health connects you with a GP for a real-time phone consultation. If the GP determines a certificate is clinically appropriate, it is issued and emailed the same day. From $9.99. Full refund if not approved.
Frequently asked questions
Employers can request a medical certificate for a single day's absence under the Fair Work Act 2009, provided the request is reasonable. There is no legal minimum number of days before evidence can be required. Check your enterprise agreement or employment contract; many set a higher threshold, such as two consecutive days.
Not automatically. Whether a certificate is required depends on your employer's policy, your enterprise agreement, and whether requesting evidence is reasonable in the circumstances. Many workplaces require evidence only for absences of two or more days, but legally, an employer can request one day if justified.
Yes. The Fair Work Act accepts either a medical certificate or a statutory declaration as 'reasonable evidence'. A stat dec is often used when a GP was not accessible. However, some enterprise agreements specifically require a medical certificate; check yours.
Book a consultation through OMC Health. Speak with an AHPRA-registered GP via real-time phone; it takes 5–15 minutes. If the GP determines a certificate is clinically appropriate, it is emailed the same day. Available 7 days a week, including weekends. From $9.99.
Not if you are a permanent employee taking genuine paid personal leave. You have a workplace right to take personal leave when genuinely ill. An employer who penalises you for taking legitimate sick leave may be in breach of the Fair Work Act's general protections provisions. Contact the Fair Work Ombudsman if this occurs.
