The rules around drug driving in New Zealand have changed, and if you’re a medicinal cannabis patient, it’s important to know what this means for you. While these new laws aim to make roads safer, they also raise concerns for patients who use prescribed cannabis products. Here’s a simple breakdown of what you need to know.
What is the New Law?
The Land Transport (Drug Driving) Amendment Act 2025 has introduced stricter regulations and penalties for driving after recent drug use in New Zealand.
From 15th December 2025, the New Zealand government and Police will implement random roadside drug testing in Wellington, with nationwide coverage expected by mid-2026. These tests will check for cocaine, methamphetamine, MDMA and THC – the compound found in some medicinal cannabis products.
If you’re pulled over, you may be asked to take a saliva swab test. If the test detects THC, you will need to take a second test straight away. If both tests are positive, you will be required to immediately stop driving for 12 hours.
Your saliva sample will then be sent to a laboratory for confirmation.
If the lab results confirm the presence of THC, you could receive an infringement notice, which may include:
- A $200 fine
- 50 demerit points on your licence
If you fail the roadside salivary test twice in 2 years and don’t have a medical defence, you’ll lose your license for 3+ months.
As of now, we know that the Police plan to use the Securetec DrugWipe 3 S device but we are unclear on the specific sensitivity levels used at the roadside. Cannabis Clinic is actively monitoring all testing-related updates and will inform patients as more information is available, so they can provide accurate advice on driving while taking prescription medicinal cannabis.
Important: Saliva tests may also detect THC from full-spectrum CBD products, as they can contain trace amounts of THC.
Blood Tests: What You Need to Know
If you refuse the saliva test or if police have reason to suspect you are impaired, they may require a blood test. Unlike saliva tests, which detect recent use, blood tests measure the amount of THC in your system. The “high-risk” threshold for blood THC levels is 3 ng/mL, which is relatively low. If your blood test exceeds this limit, you may face more serious penalties, including:
- A $4,500 fine
- Up to 3 months in prison
- A mandatory 6-month licence disqualification
Why Do We Need Roadside Drug Testing in NZ?
Driving under the influence of drugs has always been a major road safety concern. The approved Bill seeks to test for the presence of a range of drugs and serve as a deterrent, thereby decreasing the rates of driving under the influence of these drugs.
Under the current system, New Zealand police use a compulsory impairment test (CIT) if they suspect someone is driving under the influence of drugs. However, they need a ‘good cause to suspect’ the driver is impaired, and the CIT is not perfect – making it difficult to measure drug-impaired drivers.
The incoming roadside saliva drug testing allows police to test drivers for drugs anywhere, anytime, just as they do with alcohol tests.
Unlike the test for alcohol, however, the result for many of these drugs, including THC, could be returned positive, despite the person not being impaired. Unfortunately, there are not yet any quick and easy tests that can accurately test for impairment when it comes to THC.
How Long Does Medicinal Cannabis Stay in My System?
Several factors can affect how long THC stays detectable in your system:
- In frequent users, saliva tests can detect THC for up to 72 hours. For infrequent users, THC can be detected for around 12 hours.
- THC is not released from the body into saliva – it is the residual THC that remains following use that is detectable. Eating, drinking, brushing teeth and cleaning out the mouth may help decrease residual traces.
- Blood and urine tests can detect THC for much longer periods.
Even if you no longer feel impaired, THC might still be in your system and cause a positive drug test.
What Does this All Mean for Me?
We understand that this can be stressful, especially for patients who rely on medicinal cannabis to manage their health. Here are some key points to keep in mind:
1. Time Matters: When to Avoid Driving
THC can remain in saliva for several hours after use, even if you feel completely fine. To reduce the risk of testing positive, we recommend:
- Avoiding driving altogether if you feel any impairment
- Follow your doctor’s advice. Everyone’s different, but generally, we recommend waiting at least 6 hours after inhaling a THC-containing product and at least 10 hours after consuming THC orally before driving
2. Medical Defence: How We Can Support You
Medical defences do not apply at the roadside, so if your saliva test is positive, you have to stop driving for 12 hours. Medical defences can be applied for online after the time of testing to dispute infringements. If you receive an infringement notice but are prescribed medicinal cannabis and have been using it according to your doctor’s instructions, you may be able to use a medical defence to avoid fines and demerit points. To do this, you need to:
- Have an active prescription
- Follow your doctor’s guidance on how and when to use your medication
We can help you to dispute the claim with formal letters, proof of prescription and clinical backing. You can contact us for support here.
3. Our Practical Tips for Patients:
To stay safe and compliant with the law, here are some practical tips:
- Be mindful of timing: Follow the recommended waiting periods before driving.
- Practice good oral hygiene: If using a full-spectrum CBD before driving, brush your teeth and rinse your mouth after taking your medicinal cannabis.
- Keep your medical prescription active: Ensure your script is always up to date to avoid any legal complications.
- Carry your letter from us: If you are ever questioned, having proof of your legal prescription can help. You can contact us for a letter here
- Ensure the original pharmacy label is on your medication when travelling with it to confirm its prescribed status.
- Know your rights: If tested, stay calm and follow the process. If you are following medical advice, you are eligible for a medical defence.
- Seek legal support if you receive an infringement notice: Community Law Centres and the Citizens Advice Bureau (CAB) have lists of free lawyers who may be able to assist you.
What Cannabis Clinic is Doing
At the end of the day, we believe it is unfair to punish law-abiding, unimpaired patients using THC in accordance with their doctor’s guidance. The current approach is discriminatory against medicinal cannabis users.
We’re prepared to assist our patients wherever necessary to prove that they were using their medication as clinically advised – whether they’re faced with demerit points, fines, or more serious legal consequences.
We want to open a dialogue with the Ministry and NZ Police to find an alternative testing path that creates safer roads while allowing patients to access the legal medication they have a right to.
We’re Here to Support You
At Cannabis Clinic, we are committed to supporting our patients as laws evolve. If you have any concerns about roadside drug testing and how it affects you, reach out to our team.
We’re here to help you navigate these changes and ensure you have the right documentation to protect yourself.
You can also learn more from the NZ Drug Foundation here.
Disclaimer: Medicinal cannabis and CBD oil are unapproved medicines in NZ which means that there is no conclusive evidence for their effect, apart from Sativex. Many doctors do not routinely prescribe cannabis medicines. The above article was written for general educational purposes and does not intend to suggest that medicinal cannabis can be used to treat any health condition. Please consult with your healthcare provider.