Investigations need structure
A disciplinary or workplace investigation is not just asking a few staff members what happened. If the investigation is weak, biased, vague, or incomplete, the employer's later decision may be attacked as unjustified.
Anderson Law assists employers with investigation planning, complaint triage, allegations, witness questions, evidence review, investigation letters, suspension issues, investigation reports, and disciplinary steps that follow an investigation.
The investigation should be proportionate to the issue. A minor workplace concern may not need a formal external investigation. A serious complaint involving bullying, harassment, violence, dishonesty, safety, or potential dismissal may need a much more careful process.
Investigation or disciplinary process?
Employers often confuse investigation with discipline. The investigation is about finding out what happened. The disciplinary process is about deciding what, if anything, should happen because of it.
Sometimes the same employer representative can investigate and make a decision, especially in a small business. In more serious cases, it may be safer to separate the investigator from the decision-maker.
The employer should decide the structure early. If the process is unclear, the employee may argue that the employer was fishing for reasons or had already decided the outcome.
Complaint triage
When a complaint is received, the employer should first work out what it is dealing with. Is it a bullying complaint? Harassment? Safety? Performance conflict? Personality clash? Misconduct? A protected disclosure? A complaint about management conduct?
The category matters because it affects the process, confidentiality, urgency, support, evidence, and who should handle the investigation.
The employer should also consider whether immediate interim steps are needed, such as separating staff, preserving evidence, arranging support, or considering suspension. Interim steps should not be treated as final findings.
Defining the allegations
Vague allegations create bad investigations. The person accused should generally understand what they are alleged to have done, when it allegedly happened, who was involved, and why it matters.
Allegations such as "bad attitude", "bullying", or "inappropriate conduct" may need particulars. Without particulars, the employee may not have a meaningful opportunity to respond.
Good allegation wording helps everyone. It gives the complainant a clear process, gives the respondent a fair chance to answer, and gives the employer a proper foundation for any later decision.
Evidence and interviews
An investigation may include documents, emails, text messages, CCTV, rosters, wage records, photos, customer complaints, policy documents, witness interviews, and the respondent's explanation.
Witness interviews should be planned. The investigator should ask open questions, avoid coaching witnesses, avoid promising absolute confidentiality where it cannot be maintained, and keep proper notes.
The respondent should usually be given enough information to answer the allegations. Employers must balance confidentiality with fairness, but confidentiality should not become an excuse for withholding the substance of the case.
Investigation report
In more serious cases, an investigation report can help. A report may set out the complaint, process followed, evidence considered, findings of fact, credibility issues, and whether allegations are substantiated.
The report should avoid jumping from findings directly to punishment unless the investigator has also been appointed to decide disciplinary outcome. If the investigator's role is only fact-finding, the employer should keep the disciplinary decision separate.
A sloppy report can create risk. Unsupported findings, emotional language, missing evidence, or conclusions beyond the evidence can be attacked later.
Common investigation mistakes
- not defining the allegations properly;
- investigating only evidence that supports the complaint;
- withholding the substance of allegations from the respondent;
- promising confidentiality that cannot realistically be maintained;
- not preserving evidence early;
- failing to interview key witnesses;
- allowing the complainant or manager to control the investigation;
- using leading questions that contaminate evidence;
- making credibility findings without explaining why;
- mixing investigation findings with disciplinary outcome too early; and
- not giving the employee a fair opportunity to respond before action is taken.
When an external investigator may be useful
An external investigator may be useful where the allegations are serious, senior managers are involved, there is a conflict of interest, the workplace is divided, or the employer needs independence to protect the integrity of the process.
However, external investigations can be expensive and slow. Employers should use them where the seriousness of the issue justifies it. For smaller matters, a properly managed internal process may be enough.
Frequently asked questions
Does every complaint need a formal investigation?
No. The process should be proportionate. Some issues can be addressed informally. Serious allegations need more care.
Can the employer keep the complainant anonymous?
Sometimes anonymity may be considered, but it can create fairness problems. The respondent usually needs enough information to answer the allegations.
Can the investigator also decide the outcome?
Sometimes, especially in small businesses. In serious or sensitive cases, separating the investigator and decision-maker may reduce risk.
What if witnesses refuse to cooperate?
The employer should document the attempts made and consider what evidence remains available. The process may still continue, but the limits of the evidence should be recognised.
Case law examples for disciplinary investigations
A disciplinary investigation is not just fact gathering. It is the foundation for the eventual decision. If the investigation is defective, the outcome letter often cannot fix it.
Employment Relations Act 2000, s 103A - investigation is expressly relevant
The statutory test specifically directs the Authority and Court to consider whether the employer sufficiently investigated the allegations, having regard to the resources available to the employer. A small employer is not expected to run a High Court trial, but it must still run a fair process.
Hines v Eastland Port Ltd [2018] NZEmpC 79 - sufficient investigation can defeat the grievance
Hines is useful for investigations because the Court accepted the employer had done enough. The case supports the employer argument that not every alleged defect is fatal where the investigation was sufficient and any defects did not cause real unfairness.
Mulqueen v The Merino Story (NZ) Ltd [2023] NZERA 329 - verify the complaint before relying on it
Mulqueen is a practical warning. The employer relied heavily on a customer complaint but did not adequately verify it. If a dismissal depends on a customer, client, co-worker, or manager complaint, the investigator should test the account and disclose the substance of adverse material to the employee.
Atkins v Alpine 182 Degrees Ltd [2023] NZERA 334 - specific concerns must be put clearly
Atkins shows the problem with vague disciplinary allegations. An employee needs to know the specific concerns and have a genuine opportunity to respond. General dissatisfaction, anger, or hindsight reconstruction is not enough.
Young v Port of Tauranga Ltd [2025] NZEmpC 2 - document the operational and legal context
Young is helpful where the issue involves safety, statutory compliance, or third-party regulatory requirements. The employer should document the legal or operational constraint, explain it to the employee, ask for relevant information, and record why alternatives were or were not workable.
Investigation file structure
For an employer, a good file should have a clean chronology, copies of the allegations, documents provided to the employee, witness notes, the employee's response, the investigator's factual findings, the decision-maker's reasoning, and evidence that alternatives to dismissal were considered where relevant.
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