How Long Do Workplace Investigations Take? A Realistic Timeline (Not the One HR Textbooks Give You)

If you’re Googling “how long do workplace investigations take,” I’m going to guess you’re in one of two camps. Either you’re the employer who just received a complaint and you’re trying to figure out how long your life is going to be disrupted. Or you’re the person who made the complaint and you’re wondering why it feels like everyone has forgotten about you.

Either way, you want a number. So here it is.

The Short Answer

Most workplace investigations take between 2 and 8 weeks. Some wrap up faster. Some drag on for months. I know that’s not the precise, satisfying answer you were hoping for, but workplace investigations aren’t flat-pack furniture  – they don’t come with a predictable assembly time.

What I can tell you is what determines whether your investigation lands at the shorter or longer end of that range. And as someone who’s conducted numerous workplace investigations for over 15 years, I can tell you the factors that blow out timelines are almost always avoidable.

What Actually Affects the Timeline

1. The Complexity of the Complaint

A single allegation of inappropriate behaviour with two witnesses? That’s a relatively contained investigation  – potentially 1–3 weeks. Six allegations of bullying spanning two years with twelve witnesses and a paper trail that looks like it was shredded and reassembled by a toddler? You’re looking at 6–8 weeks minimum.

The scope of the investigation is the single biggest factor in how long it takes. More allegations mean more witnesses, more documents to review, and more findings to write up. It’s not complicated maths  – it’s just reality.

2. Witness and Party Availability

This is the timeline killer that nobody talks about. I can have my diary cleared and ready to go, but if your key witness is on annual leave in Bali for two weeks, we’re all waiting. If the respondent is on stress leave and their doctor says they can’t participate for a month, we’re waiting for that too.

People also cancel interviews. Reschedule. Get sick. Have family emergencies. These are humans, not calendar entries, and investigations have to work around real lives. I’ve had investigations delayed by weeks because one critical witness kept rescheduling.

3. How Quickly the Organisation Moves

Here’s a hard truth: the biggest delays in workplace investigations usually come from the organisation itself, not the investigator.

I regularly see weeks lost to internal decision-making. Who should we appoint? Do we need an external investigator? Should we get legal advice first? Should we wait until after the restructure? Meanwhile, the complainant is sitting at their desk every day wondering if anyone actually read their complaint.

My advice? Once you receive a complaint, make a decision within 48 hours about how you’re going to handle it. That doesn’t mean you start interviews immediately  – it means you decide on your approach, appoint your investigator, and communicate with the parties. Speed at this stage sets the tone for the entire process.

4. The Volume of Documents

Some investigations involve a handful of emails. Others involve hundreds of documents  – emails, text messages, CCTV footage, performance reviews, policy documents, and the complainant’s own 47-page diary of events (yes, this happens more than you’d think).

Document review takes time. Good investigators don’t skim  – they read everything, cross-reference it, and use it to inform their interview questions. If you want a thorough investigation, you need to factor in time for this.

5. Procedural Fairness Requirements

This is non-negotiable and it adds time. Every person against whom allegations are made has the right to know what’s been alleged and to respond. This isn’t optional  – it’s a legal requirement under Australian workplace law, and skipping it is one of the fastest ways to have your investigation findings thrown out.

What does this look like in practice? The investigator interviews the complainant first, then puts the key allegations to the respondent  – often in writing  – and gives them a reasonable time to respond. The respondent’s response is then considered before any findings are made. This process is important and non-negotiable, but it adds at least a week or two to most investigations.

A Realistic Timeline: What Each Phase Looks Like

Here’s roughly how a standard workplace investigation breaks down:

Scoping and planning (2–5 days): Defining the terms of reference, identifying witnesses, gathering initial documents, and getting the logistics sorted.

Interviews (1–4 weeks): The most variable phase. Depends entirely on how many people need to be interviewed and how available they are. Each interview typically runs 1–2 hours, and the investigator needs time to prepare, conduct, and write up notes for each one.

Document review and analysis (3–7 days): Often happens concurrently with interviews, but complex matters may need dedicated time for this.

Procedural fairness (1–2 weeks): Putting allegations to the respondent and allowing them time to respond.

Report writing (1–2 weeks): Preparing a detailed investigation report with findings and, where appropriate, recommendations. This isn’t a rush job  – a good report needs to be thorough, well-reasoned, and legally sound.

Red Flags: When an Investigation Is Taking Too Long

While some investigations legitimately take longer, there are warning signs that something has gone wrong:

If it’s been more than two weeks and nobody has been interviewed yet, ask questions. If you haven’t received any update in three weeks, that’s a problem. If the investigation has been going for three months with no end in sight, something is fundamentally broken  – either the scope has ballooned, the investigator is overwhelmed, or the organisation is dragging its feet.

Delays aren’t just inconvenient  – they’re harmful. For the complainant, every extra week feels like the organisation doesn’t care. For the respondent, it’s weeks of having allegations hanging over their head. And for the rest of the team, it’s weeks of tension, gossip, and uncertainty. Dragging out investigations costs organisations far more than just the investigator’s fees.

The Psychosocial Risk Factor: Why Timeline Matters More Than Ever

If you haven’t been paying attention to the changes in workplace health and safety laws, now’s the time to start. Under the updated WHS regulations, employers have a positive duty to identify and manage psychosocial hazards in the workplace. And unresolved complaints? Investigations that drag on without communication or resolution? Those are psychosocial hazards.

Think about it. A complainant who’s raised a bullying allegation and heard nothing for six weeks is sitting in a psychologically unsafe workplace every single day. A respondent with allegations hanging over their head and no indication of when it’ll be resolved is experiencing chronic workplace stress. The rest of the team, walking on eggshells because they know something is going on but nobody’s telling them anything? That’s a toxic work environment brewing in real time.

This means the timeline of your investigation isn’t just an operational issue  – it’s a safety issue. Regulators like SafeWork are increasingly looking at how employers manage the process around complaints, not just the outcome. A substantiated finding delivered six months late, with no interim risk management, no communication, and no support for the parties? That’s a failure, even if the final report is excellent.

What does this mean practically? It means that while the investigation is underway, employers need to be actively managing the psychosocial risks created by the situation. That might include adjusting reporting lines, offering EAP support, checking in with affected parties, or making temporary changes to work arrangements. The investigation doesn’t happen in a vacuum  – people still have to come to work every day while it’s going on, and they need to feel safe doing so.

How to Keep Your Investigation on Track

After years of doing this, here’s what I know works:

Act quickly once a complaint is received. Don’t let it sit in someone’s inbox for two weeks while you figure out what to do. Appoint an investigator, set terms of reference, and get moving.

Decide early whether to go internal or external. This is one of the first decisions you need to make, and it matters more than people think. If the complaint involves senior leadership, if there’s any perception of bias, or if your HR team is too close to the parties involved, an internal investigation is going to struggle for credibility – no matter how well it’s conducted. Trust in the process is everything. If the people involved don’t believe the investigation is independent and impartial, your findings won’t be worth the paper they’re written on. When in doubt, go external. The cost of an external investigator is nothing compared to the cost of an investigation nobody trusts.

Choose the right investigator from the start. An experienced workplace investigator will scope the investigation properly, manage the process efficiently, and not let things drift. If your investigator doesn’t give you a rough timeline at the outset, ask for one.

Make witnesses available. This is the employer’s responsibility. Direct witnesses to cooperate and make themselves available for interviews within a reasonable timeframe.

Have your documents ready. When the investigator asks for policies, employment records, or emails, get them across quickly. Every day you take to find documents is a day added to the timeline.

Communicate with the parties. Regular updates, even if it’s just “the investigation is ongoing and we expect it to be completed by nominated date,” go a long way toward managing expectations and maintaining trust in the process.

The Bottom Line

A well-run workplace investigation should take weeks, not months. If your investigation is dragging on indefinitely, the problem is rarely the complexity of the matter  – it’s the process around it.

Get the right investigator, give them what they need, and hold everyone accountable for keeping things moving. Your people deserve a timely resolution, and your organisation deserves findings it can actually rely on.

Need a workplace investigation conducted properly and efficiently? Segal Conflict Solutions provides independent, external workplace investigations in Sydney and across Australia. Get in touch for a confidential discussion about your matter.