90-Day Trial Periods: How to Use Them Fairly, Legally and Without Fear (NZ + Australia Guide)

Few employment tools are as misunderstood — or as misused — as trial periods.

In New Zealand, 90-day trial periods are legally available to many employers, but only if used correctly.

In Australia, employers use probation periods, which serve a similar purpose but operate under different legal rules.

Across both countries, employers often:

  • rely too heavily on trial/probation periods,
  • misunderstand what they can (and can’t) do,
  • fail to document properly,
  • skip feedback conversations,
  • avoid early intervention,
  • mishandle terminations,
  • or accidentally invalidate the entire clause.

The good news?
When used properly, trial and probation periods create clarity, fairness, and confidence — for both employer and employee.

Here’s the HR Unlocked guide to using them safely and effectively.

1. Trial period vs probation period: know the difference

New Zealand — 90-day trial period

A trial period is only valid if:

  • the business has 19 or fewer employees at the time of hiring,
  • the clause is correctly worded in the employment agreement,
  • the agreement is signed before the employee starts work,
  • the employee is a new employee (not previously employed),
  • termination during the trial is done lawfully.

If any of these are incorrect → the trial period is invalid.

Australia — probation period

Probation periods:

  • are set out in the employment contract (usually 3–6 months),
  • allow simplified termination processes,
  • still require procedural fairness,
  • still require notice or payment in lieu,
  • do NOT eliminate unfair dismissal risk for all employees (especially after 6 months or 12 months depending on business size).

Both systems allow early-stage exit — but neither allows unfair or unlawful process.

2. The biggest mistake employers make: assuming a trial/probation means “we can do whatever we want”

Trial and probation periods do NOT:

  • allow unlawful discrimination,
  • allow unfair treatment,
  • allow termination without documentation,
  • allow ignoring safety or wellbeing concerns,
  • replace good faith or procedural fairness,
  • excuse a lack of feedback.

Trial and probation periods reduce risk — they don’t eliminate it.

3. The purpose of trial/probation periods (plain English)

They exist to:

  • assess capability,
  • assess suitability for role,
  • assess team fit,
  • identify training needs,
  • identify gaps early.

They are not a quiet exit strategy for poor recruitment practices.

4. The HR Unlocked 5-Step Framework for Managing Trial/Probation Periods

Step 1: Set clear expectations from day one

Clarity reduces fear and misunderstandings.

Cover:

  • role responsibilities,
  • training plan,
  • KPIs,
  • behavioural expectations,
  • communication style,
  • check-in schedule.

Provide a written onboarding plan.
If there is no clarity, you cannot safely terminate later.

Step 2: Schedule regular check-ins

Minimum best practice:

  • weekly in the first month,
  • fortnightly thereafter,
  • documented after each meeting.

Each check-in should cover:

  • what’s going well,
  • what needs development,
  • support provided,
  • expectations for next period.

Employees should never be surprised by a termination decision.

Step 3: Provide early and specific feedback

Most trial/probation period failures happen because feedback was:

  • absent,
  • vague,
  • too late,
  • or emotionally charged.

Use neutral, factual phrasing:

  • “I noticed…”
  • “I’d like to see more of…”
  • “What support would help you with…?”
  • “Here’s the standard for this task — let’s walk through it together.”

Feedback + support = fairness.

Step 4: Document concerns and support

Documentation protects both the employee and the employer.

Record:

  • examples of performance issues,
  • training provided,
  • support offered,
  • behavioural concerns,
  • alignment to expectations,
  • employee feedback,
  • check-in notes.

If you can’t demonstrate fairness → you can’t defend the decision.

Step 5: Make the decision BEFORE the end date

This is critical in both jurisdictions.

In NZ:

If the trial period expires, you lose the right to use it — even by one day.

In Australia:

If the probation period expires and the employee crosses the unfair dismissal eligibility threshold, your risk increases dramatically.

Always diarise:

  • the review date,
  • the cut-off date,
  • the decision date,
  • the meeting date.

Never leave it to the last day.

5. How to safely terminate during a trial/probation period

Even under a trial/probation period, you must:

  • act in good faith,
  • communicate respectfully,
  • provide clear reason (NZ: reason not legally required, but best practice to give it),
  • follow contractual notice requirements,
  • pay out entitlements correctly,
  • avoid discriminatory or retaliatory reasons,
  • document the decision.

A safe script:

“We’ve reviewed your progress during your trial/probation period. Unfortunately, despite support and feedback, the role is not the right fit at this time. Your employment will end on [date], and we will pay notice as required.”

Short. Clear. Respectful.

6. When trial/probation should NOT be used

Avoid using trial/probation for:

  • misconduct (use a disciplinary process),
  • medical incapacity issues,
  • personal conflict without context,
  • lack of training or support,
  • situations where expectations were unclear,
  • employees who have been given contradictory messages,
  • roles requiring long ramp-up periods where a trial period is unrealistic.

Using trial/probation incorrectly creates legal risk.

7. The human side: trial/probation periods cause anxiety — reduce it with communication

Employees often feel:

  • insecure,
  • unsure what “good” looks like,
  • afraid to ask questions,
  • overwhelmed,
  • confused about expectations.

Your job is to:

  • normalise feedback,
  • create predictability,
  • encourage questions,
  • build safety,
  • reduce ambiguity,
  • support learning.

One HR Unlocked client said:

“Once we learned how to run trial periods properly, we kept better people — and exited the wrong hires without conflict.”

Structure protects people — on both sides.

The bottom line

Trial and probation periods are powerful tools when used properly — but dangerous when used casually.

Across NZ and Australia, the safest and most effective approach is to:

  • set clear expectations,
  • check in regularly,
  • document everything,
  • provide early, specific feedback,
  • support the employee,
  • make timely decisions,
  • handle exits respectfully,
  • treat people with dignity.

Handled well, trial/probation periods strengthen fairness, reduce conflict, and protect your organisation from unnecessary risk.

If you want ANZ-ready trial period clauses, onboarding plans, feedback templates, termination scripts and probation review tools, HR Unlocked gives you everything you need — without the consulting fees or the legal jargon.

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