Patient guide
Medicinal cannabis and workplace drug testing
If you hold a prescription and your workplace tests for drugs, this guide covers what the tests detect, industry rules and what to tell your employer. It is general information, not legal or medical advice.
Verified against Commonwealth and state sources on 28 October 2026. Laws and policies change; check the official pages before you rely on this.
The short answer
- Workplace drug tests screen for THC whether or not it came from a prescribed medicine.
- We found no Australian law that makes a prescription a general defence to a positive workplace test. Your employer’s policy, your employment terms and safety law decide what happens next.
- Aviation, rail and Queensland coal mining have testing rules set by law, and a rail safety worker must not work with any THC present.
- WorkSafe WA says that if impairment in your role may present a risk, you are responsible for telling your employer about your prescription.
- A dismissal after a positive test is not automatically fair, and an unfair dismissal application must be made within 21 days.
At a glance
Who sets the rule where you work
| Type of work | What sets the rule | After a positive test |
|---|---|---|
| Most workplaces | Your employer’s drug and alcohol policy | Whatever the policy and your employment terms provide |
| Aviation | CASA, Part 99 of the Civil Aviation Safety Regulations | No safety-sensitive work until a medical review officer clears you |
| Rail safety work | Rail Safety National Law (ONRSR) | An offence, with a maximum penalty of $10,000 |
| Queensland coal mines | Coal Mining Safety and Health Regulation 2017 (Qld) | Handled under the mine’s fitness-for-work system |
| Driving | State and territory road law | Not a defence in most states; see our driving guide |
Current at 28 October 2026. General information, not legal advice.
Start here
Three things that hold in almost every workplace
-
The test finds THC, not the reason it is there
A positive screen does not show whether the THC came from a prescribed medicine.
-
A positive result is not proof of impairment
WorkSafe Victoria tells employers that a positive drug test is not always directly related to impairment, and that false positives can happen.
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Your workplace policy sets the consequences
Employers word their rules on prescribed medicines differently, so read yours before you need it.
How testing works
What workplace drug tests detect
Workplace testing usually follows one of two Australian Standards: AS/NZS 4308 for urine (Standards Australia lists the 2023 and 2008 editions as current) and AS/NZS 4760:2019 for oral fluid. WorkSafe Victoria advises employers to test under these standards and to state their cut-off points for a positive result. Standards Australia sells the standards, so ask your employer for the policy that names the cut-offs.
CASA lists cannabinoids among the drugs it tests for, and the rail regulator lists THC as a drug a rail safety worker must not have in their system. CASA requires an aviation organisation to consult a medical review officer when a second test is positive, because medical treatment or another factor may have affected the result.
The general rule
Your prescription and your employer’s policy
SafeWork NSW says employers must take proactive steps to manage the risks of alcohol and other drugs at work. Section 28 of the Work Health and Safety Act 2011 (Cth) requires a worker to take reasonable care for their own and others’ health and safety, and to co-operate with any reasonable health and safety policy notified to workers, which usually includes the drug and alcohol policy.
We found no law that turns a prescription into a general defence to a positive test, so the policy wording matters. The council policy in the Mills case below barred prescription drugs only in a quantity that made a worker unfit or unable to work safely. SafeWork NSW notes that some industries prohibit any drugs at work, legal or illegal. If you drive for work, read driving and your prescription as well.
Safety-critical work
Industries with their own testing laws
Aviation
Part 99 of the Civil Aviation Safety Regulations covers safety-sensitive aviation activities. CASA tests oral fluid for drugs including cannabinoids. A positive screen is retested and sent to a laboratory, and you stop safety-sensitive work until a medical review officer has assessed you and found you fit. Refusing a CASA test is a criminal offence.
Rail
Under the Rail Safety National Law, a rail safety worker must not carry out rail safety work with any presence of a "prescribed drug". That is a legal term for a listed drug, and ONRSR lists cannabis (THC), methamphetamine and MDMA. The maximum penalty is $10,000, and the operator’s own drug and alcohol management program can bring disciplinary action too.
Queensland coal mining
Section 42 of the Coal Mining Safety and Health Regulation 2017 (Qld) requires every coal mine to oblige workers to notify the site senior executive of current medication that could impair their ability to do their duties. The mine must also run voluntary self-testing, random testing and testing on reasonable suspicion. For other mines, check your site’s own rules.
In the Mills case, the employer had not been told about a change in medicine before the test.
Disclosure and privacy
Telling your employer
WorkSafe WA says that if impairment in your role may present a risk, you are responsible for telling your employer so it can assess the risk, and that employers should offer a confidential way to notify them and a fitness-for-work assessment that includes medical advice.
The OAIC explains that a private sector employer’s handling of employee records is exempt from the Privacy Act where it relates directly to your employment, though collecting your health information generally needs your consent and must be reasonably necessary. The exemption does not cover contractors or volunteers. Australian Government staff are covered by the Privacy Act, and state and territory public sector staff should ask their state or territory privacy regulator.
If your employer asks what paperwork you hold, our guide to a SAS-B approval and a prescription explains the difference.
Practical steps
What you can do now
- Read your workplace’s drug and alcohol policy, including its rules on prescribed medicines.
- Ask your prescriber about effects on your work, and whether they can write a letter confirming your prescription and any work considerations.
- If your role is safety-critical, tell your employer through its confidential process, and again whenever your prescription changes.
- Talk to HR, your health and safety representative or your union.
- Get independent advice before any disciplinary meeting.
Your rights
Discrimination and unfair dismissal
The Fair Work Ombudsman explains that an employer cannot take adverse action, such as dismissal, against an employee because of a protected attribute, including physical or mental disability. Action that relates to the necessary requirements of the job is not discrimination. The Australian Human Rights Commission administers the Disability Discrimination Act 1992, which applies to employment and covers people with illnesses and medical conditions. Whether either applies depends on your facts.
Unfair dismissal law asks whether a dismissal was harsh, unjust or unreasonable, and an application to the Fair Work Commission must be made within 21 days after the dismissal takes effect. In Mills v Glamorgan Spring Bay Council [2025] FWC 116, a Tasmanian council dismissed a works officer after a random test found THC. He had disclosed an earlier prescription but not a change to a medicine containing THC. The Commission made no finding of impairment and held the non-disclosure a valid reason, but found the dismissal unfair because the non-disclosure was unintentional and the council had not considered the options in its own policy. It ordered reinstatement. A Full Bench refused permission to appeal ([2025] FWCFB 69), noting the decision was confined to its own facts.
Where to get help
Who can help
- Fair Work Ombudsman, for your workplace rights.
- Fair Work Commission, for unfair dismissal applications.
- Australian Human Rights Commission, or your state or territory anti-discrimination body.
- Your union, for advice and representation.
- A lawyer or community legal centre, for advice on your situation.
Current at 28 October 2026. General information, not legal advice. Sources, read 28 October 2026 unless noted: ONRSR, Drug and alcohol testing (updated 10 April 2026); Coal Mining Safety and Health Regulation 2017 (Qld) s 42; Work Health and Safety Act 2011 (Cth) s 28; Standards Australia store records for AS/NZS 4308:2023, AS/NZS 4308:2008 and AS/NZS 4760:2019; WorkSafe Victoria, Guide for developing a workplace alcohol and other drugs policy (reviewed 11 July 2025); SafeWork NSW, Alcohol and other drugs; WorkSafe WA, Medicinal cannabis in the workplace; OAIC, Employment, and COVID-19: Vaccinations and your privacy rights as an employee (9 August 2021); Mills v Glamorgan Spring Bay Council [2025] FWC 116 and Glamorgan Spring Bay Council v Mills [2025] FWCFB 69. Three sites did not respond, so we read archived copies: CASA, Drug and alcohol testing (copy of 1 June 2026); Fair Work Ombudsman, Protection from discrimination at work (copy of 10 October 2026); Australian Human Rights Commission, Disability discrimination (copy of 29 November 2025).
Workplace drug testing and your prescription: common questions
Can I be sacked for using medicinal cannabis in Australia?
It can happen, and a prescription does not prevent it on its own. A dismissal must still be fair, and in Mills v Glamorgan Spring Bay Council [2025] FWC 116 the Fair Work Commission ordered a prescribed worker reinstated on the facts of that case. This is general information, not legal advice.
Is a medicinal cannabis prescription a defence to a positive workplace drug test?
We found no Australian law that makes it a general defence. Your employer’s policy, your employment terms and safety law decide what happens.
Will prescribed medicinal cannabis show up on a work drug test?
It can. Workplace tests look for THC, and a positive result shows that THC is present, not where it came from.
Do I have to tell my employer about my prescription?
It depends on your role and your policy. WorkSafe WA says you should tell your employer if impairment in your role may present a risk, and Queensland coal mine workers must notify the mine of medication that could impair them.
Can my employer ask what medication I take?
A private sector employer generally needs your consent to collect health information. Once it is in your employee record, the Privacy Act’s employee records exemption usually applies.
Can I work in mining or FIFO with a prescription?
That depends on the site’s fitness-for-work rules, and some industries prohibit any drugs at work, legal or illegal. Read the site’s policy before you start.
What happens if a pilot or rail worker tests positive with a prescription?
CASA stands the person down from safety-sensitive aviation work until a medical review officer clears them. In rail, any THC present during rail safety work is an offence.
What should I do if I test positive at work with a prescription?
Ask for the result and the policy in writing, and get advice from your union or a lawyer before any disciplinary meeting.
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