How to Conduct a Workplace Investigation in Australia

Why a structured process matters

A workplace investigation that lacks a clear, documented process exposes your organisation to unfair dismissal claims, adverse action applications, and reputational damage. Australian courts and tribunals scrutinise process as much as outcome. A well-founded decision made through a flawed process can still be overturned.

The Fair Work Act 2009 (Cth) requires employers to follow a fair procedure before taking disciplinary action. That means the respondent must know the allegation against them, have a genuine opportunity to respond, and receive a decision based on the evidence, not a predetermined outcome.

Step 1: Scope the investigation

Before you interview a single witness, define what you are and are not investigating. Scope creep is one of the most common causes of delays and cost blowouts. Document:

• The specific allegations or conduct in question
• The relevant policies or obligations allegedly breached
• Who will be investigated (respondent) and who may have witnessed the conduct
• The time period under scrutiny
• Any related matters that should be dealt with separately

A narrow, clear scope keeps the investigation defensible and protects you from allegations that the process was a fishing expedition.

Step 2: Appoint an appropriate investigator

The investigator must be independent, ideally with no prior involvement in the complaint or the relationship between the parties. In smaller organisations this may mean appointing an external investigator. The investigator should have:

• Sufficient seniority or authority to make findings
• No conflict of interest (actual or perceived)
• Competence in interviewing and evidence evaluation

Where the allegations involve potential criminal conduct, consider whether to involve law enforcement before proceeding with an internal investigation.

Step 3: Notify the respondent and secure evidence

Notify the respondent in writing that an investigation is underway. You do not need to provide full details at this stage, as doing so may give them an opportunity to destroy evidence, but they should know an investigation is occurring. At the same time:

• Preserve email and system logs (work with IT)
• Secure physical evidence (CCTV footage, access records, documents)
• Consider whether a stand-down or temporary redeployment is appropriate pending the investigation

Step 4: Conduct witness interviews

Interview the complainant first, then independent witnesses, then the respondent. For each interview:

• Record the date, time, location, and attendees
• Inform the interviewee of the purpose of the interview and their confidentiality obligations
• Use open questions and avoid leading the witness
• Take contemporaneous notes and have the witness sign them where possible

The respondent must be given the substance of the allegations against them and a genuine opportunity to respond before any findings are made. Provide them with a written summary of allegations and allow a reasonable time to prepare a response.

Step 5: Evaluate the evidence and make findings

The standard of proof in a workplace investigation is the balance of probabilities, meaning more likely than not. Weight the evidence by considering the credibility of witnesses, corroborating evidence, and any inherent implausibility.

Document your reasoning. A finding that says "we prefer the complainant's account because X, Y, and Z" is far more defensible than one that simply states "the allegation is substantiated". Be specific about which allegations are substantiated, partially substantiated, or not substantiated.

Step 6: Deliver findings and recommendations

Produce a written investigation report addressed to the decision-maker (who may not be the investigator). The report should:

• Summarise the allegations and process
• Set out the evidence considered
• Make findings on each allegation

Whether the report includes recommendations depends on the nature of the engagement. An internal investigator, such as an HR manager or in-house counsel, will often include recommendations for remedial action, such as training, policy changes, or referral to management for a disciplinary decision. An independent external investigator, however, should generally confine their report to findings of fact and leave all remedial and disciplinary recommendations to the organisation. Including recommendations can compromise the appearance of independence and expose the investigator to criticism if the recommendations are not followed.

The decision-maker then considers the findings and determines the appropriate response. Keeping the investigator and decision-maker roles separate is best practice, as it protects the organisation if the decision is later challenged.

Common mistakes to avoid

• Predetermined outcome: Starting with a conclusion and working backwards destroys credibility
• No right of response: The respondent must be given particulars and a chance to reply
• Inadequate documentation: If it isn't written down, it didn't happen
• Losing confidentiality: Gossip during an investigation can give rise to defamation claims
• Unreasonable delay: Prolonged investigations can constitute procedural unfairness