The legalities of workplace drug testing

1 Jul 2019
Author: Andrea Twaddle

In New Zealand, employers have an obligation to eliminate or minimise health and safety risks. The management of risks arising from worker drug and alcohol use, is part of that responsibility, particularly in safety sensitive workplaces.

However, testing for drugs and alcohol is already a contentious issue in New Zealand employment law. Drug and alcohol testing can be an effective measure to minimise or eliminate the risks that may arise from impairment due to drugs and alcohol. However, this must be balanced with the inherent invasiveness of such processes and the privacy implications that arise.

Getting the balance right is critical to ensure that tragic consequences that can arise from unsafe work practices are avoided, and the use drug testing does not impinge on an employee’s rights.

Get the paperwork right

Employment agreements should explicitly allow for workplace drug testing to take place. By signing the agreement, employees are then deemed to have consented to drug testing. 

An effective written drug and alcohol policy must be in place to enable workplace drug and alcohol testing to be lawfully carried out. The policy should outline the circumstances in which testing can occur in the workplace; the means of testing; the types of substances being tested for; the consequences of returning a non-negative test (or refusing to submit to a test without reasonable cause); and any support that might be available to the employee upon disclosing issues with drugs or alcohol.

Employers are entitled to introduce or make changes to a workplace drug and alcohol policy. However, this should only occur following consultation with employees. 

When is it reasonable to test?

Workplace drug and alcohol testing in the workplace will always need to be carried out in accordance with the terms of employment and workplace policies. However, the implementation of policies will be subject to an employer’s overarching employment obligations of being fair and reasonable in all the circumstances.

Workplace polices will set out whether employers may test in circumstances including: prior to employment, for reasonable cause, post incident/accident, and/or random testing

Pre-employment screening

Pre-employment drug screening is widely used in certain sectors. It can be a useful tool for employers, particularly in safety sensitive industries.

Generally, employers will require a candidate to undergo pre-employment screening. Any offer of employment made will be expressly conditional on the return of a negative test, with the employment relationship not commencing until after that time. If the prospective employee fails to return a negative test, the conditional offer of employment will not have been met.

Reasonable cause testing

It is relatively common for workplaces to have in place testing where the employer has reasonable cause to believe that an employee is at risk of impairment due to the consumption of drugs and/or alcohol.

Reasonable cause testing should be accompanied by training for managers/supervisors to enable them to identify reasonable cause indicators. Generally, a workplace policy will also set out a non-exhaustive list of indicators such as excessive lateness, odour of alcohol, violent or erratic behaviour, bloodshot eyes, or impaired motor skills.

Post-incident testing

Also relatively common, is testing for drugs and alcohol that is carried out following an incident, accident or near miss in the workplace.

Random testing                                      

Random testing is less commonly used. It may be justified, as a deterrent, and used where an employee is working in a safety sensitive area or if an employee’s work directly impacts the safety of others. These parameters should be clearly defined in workplace policies. Where random testing is in place, testing must be truly random, and not undertaken on mere suspicion of drug use.

How testing is conducted

Employers using workplace drug testing should consider whether testing should be carried out in the workplace, or offsite. All testing should be consistent with the New Zealand standards. In New Zealand, the preferred standard remains urine testing.  

Investigations and disciplinary action

Employers health and safety policies and procedures should set out clearly what will happen if an employee returns a non-negative or positive sample to a drug test, or, if they refuse to undertake reasonable testing.

Policies should set out whether and how to implement any disciplinary action. Many employers have fallen down simply by not following a fair and reasonable process, which will ordinarily include:

In accordance with their employment obligations, the next consideration is whether and how to implement any disciplinary action. If disciplinary action is taken, it is crucial to strictly adhere to the relevant drug and alcohol policy, as well as the employer’s disciplinary policy. A failure to follow policy can render any subsequent disciplinary action unjustified.

Aspects of a fair process in these circumstances will usually include:

  • giving a copy of the results to the employee and discussing it with the employee;
  • considering whether suspension is required (e.g. for health and safety reasons), and giving the employee a chance to comment on the proposed suspension before reaching that conclusion;
  • giving the employee an opportunity to comment on the test results;
  • responding to any requests for the sample to be re-tested; and
  • putting to the employee the allegation that they were in breach of the employer’s expectations regarding drugs (as set out in the employment agreement/policy), and that if proven, this could constitute serious misconduct which may result in disciplinary action including the employee’s dismissal; and
  • notifying the employee that a disciplinary meeting will be taking place to discuss the allegations, and that they may bring a support person or legal representative with them to that meeting.

An employer must consider the employee’s response to the allegations before making decisions about whether the allegations have been substantiated. The failure of a test alone will not necessarily justify dismissal. All relevant the circumstances must be considered, including the employee’s explanation. The Employment Relations Authority and Employment Court have consistently held that in order for any disciplinary action to be justified, an employer must have acted in accordance with its policy, and followed a fair and reasonable investigation/disciplinary process.

Some workplace policies will enable employees to take a period of unpaid time off work, to undertake rehabilitation and obtain support, as an alternative to dismissal. In these circumstances, the employee remains off work pending successful results from subsequent testing.


Working under the influence of drugs can have catastrophic consequences for the employee, and others in the workplace. In turn, it can be devastating for a business. Employees have a duty to keep themselves and others safe while at work, and must follow employers’ reasonable health and safety policies, as well as reasonable instructions. This will include complying with any workplace drug and alcohol policies.

A good drug and alcohol policy can be an invaluable tool to help manage health and safety in the workplace. It must be introduced and implemented fairly in order to balance employees’ rights with employers’ obligations.

For advice on health and safety, including workplace drug and alcohol testing, the DTI Lawyers specialist employment law team can assist. Please contact our experts on 07 282 0174.

The legalities of workplace drug testing
About the Author
Andrea Twaddle
Andrea is an experienced specialist employment lawyer and Director at DTI Lawyers. She advises on contentious and non-contentious employment law issues, including privacy, and health and safety matters. Andrea is AWI-CH qualified, and undertakes complex workplace investigations. She is a member of the national Law Society Employment Law Reform Committee, a former Council Member at the WBOP District Branch of the Law Society, and Coordinator of the WBOP Employment Law Committee. Andrea is a sought-after commentator and speaker on employment law issues at client and industry seminars. She provides specialist, strategic advice to other lawyers, professional advisors and leadership teams. You can contact Andrea at