The cannabis referendum: implications for workplace drug testing and policies

Friday, October 23, 2020

The outcome of the upcoming referendum on whether recreational cannabis use should be legalised will be interesting. This is a non-binding referendum, but the government has indicated that it will honour the results if re-elected. What does a yes vote mean for the workplace and how should employers approach this?

If cannabis is legalised there will be no real change in employment law. Employers will retain the ability to prohibit the consumption of substances at work, and to prohibit attending work while at risk of impairment by alcohol or drugs.

However, legislative changes provide a timely reminder for employers to review and update their policies in line with changing social norms and attitudes.

Health and safety

The starting point for the ‘cannabis and the workplace’ discussion is the obligations imposed by the Health and Safety at Work Act 2015 (HSWA).

The HSWA imposes a duty to:

  • Eliminate risks to health and safety, so far as is reasonably practicable; and
  • Where elimination is not reasonably practicable, to minimise those risks so far as is reasonably practicable.

If an employee is impaired at work (whether through alcohol, legal or illegal drug use) this may impact the health and safety of other employees. However, determining whether an employee is actually impaired can be difficult, even with a positive drug or alcohol test. Instead, employers should be testing for risk of impairment, namely by specifying (within their drug and alcohol policies) what level of drugs or alcohol present in a test constitutes a risk of impairment. Commonly employers will reference the AS/NZ 4308 standard to determine these levels.

Being at risk of impairment by alcohol on the job can be grounds for disciplinary action, despite alcohol’s legality. The same logic would apply to cannabis, if legalised. This is especially so in safety-sensitive industries, such as construction, manufacturing and jobs which involve driving.

Workplace testing

In order to carry out workplace drug and alcohol tests, an employer is required to have an employee’s consent, and a lawful ability to do so. This is usually provided for in the employment agreement or in a drug and alcohol policy. General grounds for drug testing are:

  1. Pre-employment: With the consent of the applicant as part of an assessment of suitability for the role.
  1. Post incident: After an accident or incident in the workplace. This must be provided for in the relevant employment agreement or policy.
  1. Random drug testing: The Employment Court has ruled that random drug testing can only be used for safety-sensitive roles.
  1. Reasonable cause: For example, where an employee is exhibiting behaviour that indicates they may be at risk of impairment by drugs or alcohol. There must be sufficient nexus between the ‘reasonable cause’ and the test.

Developing a policy

Your policy should set clear expectations on employees in relation to drugs and alcohol at work.

If your Drug and Alcohol Policy contemplates testing, we recommend identifying a third-party testing provider and confirm:

  • the steps for testing;
  • the substances to be tested for;
  • what constitutes a “positive” test with respect each substance and how this will be determined (including what levels of drugs or alcohol within a test correlate to risk of impairment); and
  • how test results will be provided to the employer and the estimated timelines.


In the event the referendum passes, legalisation will not come overnight, as the Bill will need to move through Parliament and the Select Committees. Should legalisation occur, it is likely that case law developments will provide greater clarity.

Workplace drug testing provides fertile ground for dispute and if cannabis use is legalised issues such as what amounts to reasonable cause and whether an employee is at risk of impairment are likely to be subject to legal challenge.

For more information, please contact a member of our employment or health and safety team.


Disclaimer: the content of this article is general in nature and not intended as a substitute for specific professional advice on any matter and should not be relied upon for that purpose.


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