Guides · updated August 2026
The s64 medical defence — for prescribed patients who failed a drug test
The short answer: if a roadside drug test picked up a medicine you take under a current, valid prescription, and you followed your prescriber's instructions, section 64 of the Land Transport Act 1998 gives you a statutory defence — the notice can be withdrawn. It exists for exactly this situation: qualifying drugs including THC from medicinal cannabis and amphetamine from ADHD medication stay detectable long after any effect has worn off. The defence is raised in writing, after the notice, before the due date — and never after paying.
The three conditions — all must hold
- The drug detected is a listed qualifying drug.
- You held a current, valid prescription for a medicine containing it at the time of the test.
- You took it as your prescriber directed — dose and timing.
To be straight about the boundary: no prescription, an expired script, or use outside the instructions, and this defence isn't available — the notice then stands or falls on other grounds. This page is for prescribed patients caught by chemistry, not a way around impaired driving, and driving while actually impaired is dangerous and remains an offence regardless of any prescription.
How the process works
- A positive roadside oral-fluid screen brings a 12-hour no-driving direction — it applies regardless of prescription, so comply.
- If the laboratory result confirms a qualifying drug, an infringement notice follows: a fine and demerit points.
- You complete the Police medical-defence application and send it with your prescription and the dispensing-container label — before the due date on the notice.
- Police assess it; if the three conditions are made out, the notice — fine and demerits together — can be withdrawn.
We fill the application out for you
Our medical-defence fast track checks the defence for free and gives you an honest estimate. If it's worth running, we pre-fill the Police application from your details for NZ$9.99 — you sign it on-screen, attach your prescription and dispensing label, and email it before the deadline. Your medication details are used only to prepare the application and are never stored.
Start the fast trackCommon questions
What is the section 64 medical defence?
Section 64 of the Land Transport Act 1998 provides a statutory defence to a drug-driving infringement where the qualifying drug detected came from a medicine you took under a current, valid prescription, following your prescriber's instructions. If the defence is made out, the infringement notice can be withdrawn. It exists because prescribed medicines — including medicinal cannabis and ADHD medication — can return positives long after any impairment has passed.
Who qualifies for the medical defence?
Three things must all be true: the detected drug is a listed qualifying drug; you held a current, valid prescription for a medicine containing it at the time; and you took it in accordance with your prescriber's instructions (dose and timing). Miss any one of the three — no prescription, an expired script, or use outside the instructions — and the defence does not apply.
What evidence do Police need for a medical defence?
The completed medical-defence application plus proof of the prescription — in practice your prescription and the dispensing-container label showing your name, the medicine, and the instructions. Send it to Police before the due date on the infringement notice. Keep the original packaging; the dispensing label is the piece people most often can't find later.
Does the medical defence work at the roadside?
No — and arguing it at the roadside achieves nothing. The defence is raised in writing after the notice is issued. The 12-hour no-driving direction after a positive screening test applies regardless of any prescription, because it's about the test result, not liability — comply with it, then raise the defence against the notice itself.
Can I still use the defence after paying the fine?
No. Police can't consider a medical defence once a notice is paid or has gone to the Ministry of Justice for collection. Paying is treated as accepting liability and ends the process — so if you're prescribed and intend to raise the defence, don't pay, and don't let the due date lapse either.
Does this cover criminal drug-driving charges too?
This guide covers infringement notices — the fine-and-demerits tier introduced with roadside oral fluid testing. If you've been summonsed to court on an impaired-driving charge (for example after a blood test or an incident), that's a criminal matter: see a lawyer or Community Law rather than relying on an infringement-track application.
I'm prescribed — can I be stopped and tested at all?
Yes. Since 1 July, Police can oral-fluid test any driver anywhere in New Zealand, prescription or not. A prescription doesn't exempt you from testing; it gives you a defence to the resulting notice if the three s64 conditions are met. It's also worth asking your prescriber about safe driving windows for your medicine — the defence requires following their instructions, and good instructions cover driving.
Related: roadside drug testing — the full picture · how demerit points work · what changed on 1 July
Sources: Land Transport Act 1998 s64 (statutory medical defence), NZ Police medical-defence application process, Police published drug-driving penalties. GetMeOff.co.nz provides automated document drafting and general information only — it is not legal advice, not medical advice, and no outcome is guaranteed. Talk to your prescriber about driving safely on your medication.