How to Run a Workplace Investigation Without Getting It Wrong

By Natasha Silveira | 2 October 2026 | 11 min read

A team leader emails you on a Friday afternoon. A staff member says a senior colleague has belittled him in meetings for months. You have a policy somewhere, but you’ve never run a formal investigation. Getting the workplace investigation process in Australia right matters more than most owners expect, because the Fair Work Commission looks hard at how you reached a decision, not just what you decided.

This guide walks through each step, from the first complaint to the final outcome, and shows where small businesses most often slip.

Why the way you investigate matters

Workplace disputes are rising. The Fair Work Commission received 44,075 lodgements in 2024 to 2025, a 10 per cent jump on the year before, and unfair dismissal claims made up 37 per cent of them, according to HR Leader’s analysis of the Commission’s annual report. Many of those claims follow an internal investigation.

When a dismissed employee challenges the decision, the Commission asks whether there was a valid reason and whether the process was fair. Its unfair dismissal benchbook says procedural fairness requires that a person be told the case against them and given a chance to answer it. A sound finding reached through a sloppy process can still lose.

The risk isn’t only legal. A complaint that drags on, leaks or ends with no clear answer damages trust across the whole team. People stop raising problems, and small issues grow into resignations or workers compensation claims.

There’s a wellbeing cost too. Safe Work Australia reports that mental health conditions made up 12 per cent of serious workers compensation claims in 2023 to 2024, with median time off almost five times longer than for other injuries. Bullying and harassment complaints left unresolved feed straight into that number.

When a complaint needs a formal investigation

Not every grievance needs a full investigation. A clash over rosters might be fixed with a facilitated conversation. A formal process is the right call when the allegation is serious, disputed, or could lead to discipline or dismissal.

Typical triggers include:

• Bullying, sexual harassment or discrimination allegations.
• Theft, fraud or misuse of company property.
• Serious safety breaches or threats of violence.
• Repeated misconduct after earlier warnings.

Sexual harassment complaints carry extra weight. Employers now have a positive duty to take reasonable steps to eliminate it, and the Fair Work Ombudsman’s guidance says to treat all reports seriously and investigate them promptly. If you’re unsure whether the matter is serious enough, treat it as if it is. Scaling back later is easier than explaining a shortcut.

Anonymous complaints are harder but not impossible. You can still look into them if there’s enough detail to test, such as dates, places or documents. Be careful not to put allegations to someone that you can’t back with any evidence. Where an informal fix is chosen instead, write down why, so you can show the complaint wasn’t simply ignored.

The workplace investigation process in Australia, step by step

Follow these steps in order. Each one builds the record you’ll need if the decision is ever tested.

1. Receive and record the complaint in writing, with dates and witnesses.
2. Manage immediate risk, such as changed rosters or paid stand-down.
3. Appoint an impartial investigator and set a written scope.
4. Gather evidence from the complainant, witnesses and documents.
5. Put the allegations to the respondent and hear their response.
6. Make findings on each allegation, with reasons.
7. Decide the outcome separately, then close the loop with both parties.

1. Receiving the complaint

Thank the person for coming forward and explain what happens next. Ask them to put the complaint in writing, or write it up yourself and have them confirm it. Record specifics: what was said or done, when, where and who saw it. Vague complaints produce vague findings.

2. Managing risk while you investigate

Think about safety first. You might adjust rosters, change reporting lines or direct the respondent to work from home. If you stand someone down, it’s normally on full pay unless their award, agreement or contract says otherwise, so check with whoever runs your payroll services before the next pay run. Make clear that a stand-down is not a finding.

Appointing the right investigator

The investigator should have no personal stake in the result. That rules out the respondent’s direct manager in most cases, along with anyone named in the complaint or close to either party. In a small business, that can mean nobody inside the company is suitable.

Consider three practical options. A senior manager from another part of the business can work for minor matters. An external HR consultant suits most bullying, conduct and performance-related complaints. A workplace lawyer or specialist investigator is the safer choice for serious harassment, fraud or matters likely to end in court.

Write the scope before you start

A short terms of reference document keeps the process on track. It should list the allegations being investigated, who will be interviewed, the documents to be reviewed, the expected timeframe and who makes the final decision. The investigator finds facts. Someone else decides the outcome. Keeping those roles apart protects you if the decision is challenged.

Agree in advance how confidentiality will work. Tell everyone involved that the matter is confidential, and that victimising anyone for making or helping with a complaint is not acceptable. Record that you said it.

Set a realistic timeframe too. Many straightforward investigations wrap up within four to six weeks, but witness leave, document requests and extensions can stretch that. Tell both parties if the timetable moves, and why.

Gathering evidence and interviewing people

Start with the complainant. Go through their account in detail and ask for anything that supports it, such as messages, emails, rosters or photos. Then interview witnesses they name, plus anyone else likely to have seen what happened.

Use open questions. “What happened next?” gets better evidence than “Did he shout at you?” Take detailed notes, and ask each person to read and sign their statement. Interview people separately and remind them not to discuss the matter.

Offer each interviewee the chance to bring a support person. Under the Fair Work Act, an unreasonable refusal to allow a support person in discussions relating to dismissal is a factor in deciding whether a dismissal was unfair. A support person can’t answer questions for the employee, but they can be there.

Procedural fairness for the respondent

This is the step that sinks most investigations. The respondent must know exactly what they’re accused of before they’re asked to answer it. Send the allegations in writing, ideally a few days before the interview, with enough detail on dates, events and people for them to respond properly.

Then let them answer fully. Ask about each allegation in turn. If they name witnesses or point to documents, follow those up. If new allegations surface, put those to them too before you rely on them.

Where the evidence includes a witness statement the respondent hasn’t seen, give them the substance of it. You don’t always have to name the witness, but the respondent should know what’s being said so they can reply to it.

Keep an open mind until the evidence is in. Investigators get into trouble when emails or meeting notes show the decision was made before the respondent spoke. If you’re also handling a related performance or termination issue, our guide on how to terminate an employee legally in Australia covers the steps that come after a finding.

Making findings you can defend

Workplace investigations use the civil standard of proof: the balance of probabilities. The question is whether it’s more likely than not that the conduct happened. For serious allegations, such as sexual harassment or theft, Australian courts expect stronger evidence before reaching that conclusion.

Make a finding on each allegation separately. Use one of three labels: substantiated, not substantiated or unable to be determined. Explain the evidence that led there, including why you preferred one account over another. Consistency, supporting documents and the plausibility of each version all matter.

Write the report plainly. A good report sets out the allegations, the process followed, the evidence, the findings and the reasons. It doesn’t recommend a sanction unless the scope asked for one.

Deciding the outcome

The decision maker reads the report and decides what happens next. Options range from no action, to training or mediation, to a written warning, to dismissal. Any disciplinary step needs its own fair process, including a chance for the employee to respond to the proposed outcome.

Tell both parties the result in a private meeting, then confirm it in writing. The complainant may not get every detail of any discipline, but they should know the complaint was taken seriously and what the finding was.

Common investigation mistakes to avoid

Complaints are more common than reports suggest. The Australian Human Rights Commission’s national survey found one in three workers had experienced workplace sexual harassment in the past five years, but only 18 per cent reported it. When someone does come forward, a poor process tells everyone else not to bother.

These are the errors we see most often:

1. Waiting too long to start. Memories fade and the complainant loses faith.
2. Using a conflicted investigator. The findings look predetermined, even when they aren’t.
3. Vague allegations. “Inappropriate behaviour” gives the respondent nothing to answer.
4. Skipping the respondent’s witnesses. Ignoring their evidence makes the process one-sided.
5. Mixing findings and punishment. The investigator recommends dismissal before the facts are settled.

One more trap catches owners who mean well: promising the complainant a particular result. You can promise a fair, prompt process. You can’t promise an outcome before the evidence is in.

Prevention reduces the number of investigations you need. Clear policies, training and consistent decisions all help, and our employer’s playbook for preventing workplace discrimination sets out eight practical steps.

After the investigation

The end of the report isn’t the end of the job. Check in with the complainant and the respondent over the following weeks. Watch for signs of retaliation, gossip or people taking sides, and act early if you see them.

Look for what the complaint tells you about the wider team. Was there a policy gap? Did a manager miss early warning signs? A short review can stop the same problem coming back. If the outcome leaves a role vacant, a structured hiring process such as VeiraMal’s RPO services helps you fill it without rushing.

Store the file securely and limit who can see it. Keep the complaint, notes, statements, report and outcome letters together. If a claim arrives months later, that file is your evidence.

Most small businesses only run an investigation once every few years, so it’s normal not to have the process memorised. VeiraMal’s outsourced HR services can scope, run or review investigations for SMEs in Melbourne, Sydney and Hobart. For a quick read on a complaint you’re dealing with, call VeiraMal directly or send a message through the contact form.

Frequently asked questions