Before taking disciplinary action or responding to a complaint, an employer should find out as much as they can.

When is an investigation needed?

An employer may need to investigate an issue involving an employee, for example, if there has been possible misconduct, or a complaint of bullying, harassment or discrimination. A proper investigation has a number of steps and decisions to be made.

Employers need to balance:

  • advising an employee that there is a concern or suspicion (an allegation) about something they have done, or not done
  • unnecessarily raising something that may not be a real issue, causing stress to the employee. There may be times when an employer does not know who is responsible, for example, when there has been a theft.

An investigation may be quite simple or it may be complex and include examining documents and data, and interviewing people who witnessed the misconduct or behaviour. The approach will depend on the situation.

Principles for investigations

Investigations must be carried out in good faith and use the principles of ‘natural justice’. This includes not jumping to conclusions. A test for this is: ‘what a fair and reasonable employer would have done’.

Key elements of a fair investigation

These will vary, depending on the facts. However, the basics are that:

  • an employee should be told the details of the allegation. However, getting the timing right for this can be a challenge. Employers need to have enough information to be confident that there is an issue without undertaking a full investigation before advising the employee. Usually, once an employer feels that there is an issue to be answered, it is appropriate to put this to the employee and advise them that a full investigation will be undertaken. However, in some situations — for example, where there is information that could be destroyed or people threatened — employers may want to resolve these matters before talking to the employee
  • an employee should be given a reasonable opportunity to respond
  • any explanations should be fully considered before conclusions are made.
    Investigations can be time-consuming and sometimes expensive. Deciding the best approach can be challenging for any organisation.

It is not a requirement to use an independent investigator (someone other than the manager who will make the final decision on any action to be taken), as long as the person who gathers the facts and does the investigation is neutral, does not take sides, and considers all the information in a balanced way.

However, using another manager, Human Resources, or someone external to gather the facts and present these in a balanced way can be useful.

External independent investigators

A larger organisation may be able to use their Human Resources, Audit and Risk, or Health and Safety teams — this may not be possible for a small organisation. An organisation may choose to use an external investigator when an investigation involves:

  • difficult or complex issues, for example, a fraud or drug use allegation
  • a risk of a toxic work environment, for example, a complex bullying allegation
  • sensitive allegations, for example, a sexual harassment allegation (often policies have time constraints on the follow-up process that need to be complied with)
  • questions of credibility, for example, when the allegation of inappropriate behaviour is made by a customer about an employee (if an internal investigator is used, it may create a perception that the investigation is biased)
  • an organisation-wide issue, for example, where money has gone missing but there is no person identified as acting inappropriately, an investigator should look at all the evidence and come to a conclusion based on the facts with no bias.

If an organisation chooses to use an external independent investigator, they should be aware of the regulatory requirements for investigators. Those in the business of providing investigation services are required to be licensed under the Private Security Personnel and Private Investigators Act 2010, unless they are regulated by another act, for example, a lawyer being required to hold a practising certificate.

If employers are seeking the service of an independent investigator, they should make sure that they are engaging suitably qualified and licensed individuals. Ensuring the workplace investigator has the appropriate licence or accreditation gives assurance that they have appropriate skills and access to formal channels for making complaints.

To check whether a workplace investigator has a private investigator licence, check the Public Register.

Public register of licence & certificate holders – Ministry of Justice(external link)

If the workplace investigator is a lawyer, check if they have a practising certificate from the New Zealand Law Society.

New Zealand Law Society Te Kāhui Ture o Aotearoa(external link)

Types of investigations and who should investigate

Disciplinary investigations

  • Where possible, the investigator should be independent. Whether they are internal or external generally depends on the size and complexity of the issue.
  • Is there a need for the decision-maker to be seen as unbiased? If so, it is a good idea to use someone independent to gather the facts. This person could be internal.
  • What is required in terms of delegated authorities? If the workplace policy states that the person who gathers the information cannot be the decision-maker, then the roles will need to be separate.

Disciplinary process

Bullying, harassment or discrimination investigations

  • The investigator should be experienced and independent due to the sensitive nature of the complaint and the need to be seen as unbiased. This type of complaint is also often complex and time-consuming.
  • An investigator from Human Resources is an option.
  • WorkSafe can investigate bullying complaints.

Bullying, harassment and discrimination

Health and safety investigations

This can be a specialist area and whether you go external will depend on the nature of the health and safety investigation — for example, was it a serious harm incident?

Team dysfunction/relationship breakdown investigations

This can be an issue if there is high turnover or low employment satisfaction survey ratings. These investigations will often be undertaken by Human Resources or someone external.

Work relationship problems

Prepare for the investigation

  • Check the and policies.
  • Decide who you want to carry out the investigation.
  • Plan the investigation and draft the Terms of Reference.
  • Once it is known who the investigation is about, share the draft Terms of Reference with the employee (as well as the person who has made a complaint if it affects them personally, for example, bullying) and get their feedback.

Terms of Reference

The Terms of Reference document is a roadmap for the investigation. It should:

  • identify the matters to be investigated and the limits of the investigation, including what is outside the scope of the investigation
  • set out the nature of the issues/allegations/complaint
  • say who the investigator will be
  • state what process will be followed (if using an independent investigator then the employer is still responsible for the investigation)
  • refer to the relevant work rules, codes, policy and procedures
  • where possible, identify who should be interviewed — the list of who should be interviewed may change as the interview progresses
  • give timeframes (likely to shift)
  • set out that the role of the investigator is not the same as the role of the decision-maker — this is to make it clear that the investigator’s role is to determine the facts, not decide any disciplinary outcome
  • make it clear that anyone can have a support person or representative in interviews at any time in the process
  • set out what the report at the end of the process will contain
  • advise who the draft report will be given to for comment, prior to finalising
  • advise who the sponsor or manager responsible is and who the contact person is.

The draft Terms of Reference should be given to the complainant, and any employees whose conduct is under investigation, for feedback before finalising.

Conducting an investigation


  • Witnesses are those people who saw the act or behaviour and/or have direct knowledge or experience of what is said to have happened.
  • Employees are entitled to know the identity of witnesses so they can respond to them fully.
  • Witnesses should not be anonymous or be able to make off-the-record comments.
  • Witnesses should be told that the information they give will be confidential to the investigation, but that the person whose conduct is under investigation will be given the notes, or summary of meeting notes, and these will identify them.
  • In very rare cases it may be acceptable for witnesses to be anonymous, but there needs to be a good reason for this and enough information — without identification — for the employee to give a reasonable response. It is best to get expert advice if you are considering this.

Interviewing witnesses

  • Identify who you need to interview. Think about how wide you need to go. Try not to make the investigation wider than is needed, while making sure that you do not leave important questions unanswered.
  • Be clear with the person being interviewed what the purpose of the interview is and what the information will be used for.
  • Ask open-ended questions that cannot be answered with ‘yes’ or ‘no’, and follow up with clarifying questions.
  • Record the interview. This can be done electronically (if you get permission from the person being recorded) or by taking notes, or a mixture of these.
  • Confirm the meeting notes back with the witness before you give these to the employee concerned.

Interview the employee concerned

  • Provide all documents and summaries of what the other people interviewed (witnesses) have said in advance.
  • Invite the employee to have a representative.
  • Record (with permission) or take notes of the interview.
  • Request comments and confirmation of notes.
  • Follow up with further questions, if needed.

The report

The report should:

  • contain findings — a careful balanced assessment of what has been learned and whether the allegations are more likely to have been true than not
  • address each concern or issue raised
  • contain the reasons for the findings, and keep emotions or moral judgements out of the process
  • have a clear link or reference back from the findings to the evidence
  • be provided to the employee for comment (and possibly to the complainant — refer to the Terms of Reference) before being finalised
  • not contain a decision or recommendation on what disciplinary action should be taken.

Things to remember

  • When interviewing, do not talk too much — use who, what, when, how and why questions, and then listen.
  • Do not end the interview just because you have no more questions. At the end of an interview, ask if there is anything the person wants to ask or tell you, or thinks you should know.
  • Be sure that the investigation supports the report findings.
  • Be careful to put all the information you have relied on in the report.
  • Take careful meeting notes.
  • Do not have off-the-record conversations.
  • Do not talk to people about potential findings while you are investigating.
  • Do not ignore facts because they are inconsistent with other information.
  • It is important that the report is complete, fair and neutral. Do not rush the process.
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