Medical Certificates for Sick Leave – What Employers Need to Know
When an employee calls in sick, most employers want to be supportive—but you also need to manage business continuity and protect against potential misuse of leave. That’s where medical certificates come in.
Handled well, requesting a medical certificate is a straightforward way to balance compassion for your team with clear processes that keep your workplace running smoothly.
When Can You Request a Medical Certificate?
Under New Zealand employment law, an employer can ask for proof of sickness or injury after three or more consecutive calendar days of sick leave—even if some of those days aren’t working days.
You can also request proof sooner than three days if it’s reasonable, but in those cases, you must cover the cost of the medical certificate.
Example: If an employee calls in sick on Friday, Monday, and Tuesday, you can request proof of illness from their doctor because it spans three consecutive days.
What Should a Medical Certificate Include?
A compliant medical certificate should confirm:
That the employee is unfit for work due to sickness or injury.
The date the medical assessment took place.
The expected timeframe for their absence.
It should not detail the specific medical condition—protecting the employee’s privacy is essential.
Best Practice for Employers
Be consistent – Apply your medical certificate policy the same way for all employees to avoid claims of unfair treatment.
Make it clear upfront – Include your requirements for medical certificates in your employment agreements and sick leave policy.
Cover the cost when required – If you request proof before three days, pay the cost directly or reimburse the employee promptly.
Keep it confidential – Treat all medical certificates as private information and store them securely.
Why This Matters
From a business perspective, medical certificates help you:
Confirm genuine sick leave and plan resourcing accordingly.
Identify patterns that may signal wellbeing issues or misuse.
Maintain fairness and transparency across the team.
From a people perspective, a clear policy builds trust. Employees know what’s expected, and managers can respond with empathy backed by process.
Medical certificates aren’t about catching people out—they’re about creating a workplace where everyone can take the time they need to recover, while keeping the business on track.