Since 1 July, New Zealand Police can pull over any driver, anywhere, and run a roadside drug test — the same way they've long been able to for alcohol. The oral-fluid testing regime that started as a Wellington pilot in December 2025 is now operating nationwide, and the early numbers are in: by mid-May, across the first five districts to get it, police had run nearly 1,500 screening tests with 52 coming back positive — a 3.6% positivity rate, in line with what police see from roadside breath testing. In Dunedin, where testing started with the nationwide switch-on, the local road policing manager told the Otago Daily Times his staff had already run about 100 tests within two weeks:
"Some people you would never think are on drugs are coming back [as being] on drugs ... just normal people you would never think would be on drugs."
That's the headline. The part worth your attention is what actually happens between the roadside swab and the notice in your letterbox — because this is a genuinely new kind of infringement, built differently to every camera or officer ticket this site usually covers.
How a swab becomes an infringement notice
The process runs in stages, and it's worth knowing where the actual penalty comes from. Police describe it like this:
- A first screening test — a tongue swipe, a few minutes at the roadside.
- If that's positive, a second screening test follows.
- Two positives and you're prohibited from driving for 12 hours on the spot, regardless of what happens next.
- The saliva sample from that stop goes to a lab, which checks for 25 "qualifying drugs." The infringement notice — the fine and the points — comes from the lab result, not the roadside swab.
That last point matters. Unlike a speeding ticket, where the number on the notice is the number the camera or the officer's device recorded, a drug-driving infringement is a two-step process with a delay in the middle. You could be cleared roadside on the second test and still receive a notice weeks later once the lab result comes back, or vice versa.
The demerit maths nobody's flagging
Here's the number that deserves more attention than it's getting. Police's penalties and outcomes schedule sets the fine and points like this:
- One qualifying drug confirmed by the lab: $200 fine, 50 demerit points.
- Two or more qualifying drugs: $400 fine, 75 demerit points.
- Refusing or failing to comply with testing: $400 fine, 75 demerit points, plus the 12-hour ban regardless.
Our own guide to demerit points covers the number that gives those figures teeth: 100 points inside a rolling two-year window means a three-month licence suspension. A single two-drug (or refusal) infringement is 75 of those 100 points, gone in one stop — more than any officer-issued speeding ticket carries on its own, and enough on its own to push most drivers into suspension territory if they've picked up anything else in the past two years. No other single infringement notice in New Zealand hits the demerit ledger that hard.
The one recognised defence — and it's narrow
There's a genuine, statutory defence here, but it doesn't apply to everyone and it doesn't apply at the roadside. Section 64 of the Land Transport Act 1998 provides a medical defence: if the drug the lab found was prescribed to you and you took it exactly as your prescriber directed, the infringement can be withdrawn. It's most relevant for prescribed medicinal cannabis and some ADHD medications, both of which can register on a lab test days after any effect has worn off.
Two things to be clear-eyed about. First, the defence doesn't touch the 12-hour driving prohibition — that stands regardless of any prescription you hold. Second, it isn't automatic: you have to raise it against the infringement notice itself, in writing, before the due date, with proof of the prescription and confirmation you followed it. We cover the full process — including the form Police require — in our dedicated roadside drug testing guide.
Outside that narrow lane, there's no general "I wasn't actually impaired" ground written into the infringement scheme — the lab-confirmed presence of a qualifying drug is the offence, not a judgment call about how it affected your driving that day.
What this means if it lands on you
Most of these tests will be accurate, and the plain advice hasn't changed: if you're taking anything that can impair you, don't drive. But if a notice arrives and you're a prescribed patient who followed your prescriber's directions, the medical defence is worth pursuing properly rather than ignored — and like any NZ infringement, that means acting in writing before the deadline, not after. Our free check can tell you whether your notice fits that ground, and our guide to what happens after a decline covers where things go if it doesn't.
Sources: RNZ, "Roadside drug tests rolling out nationwide"; Otago Daily Times, "'Surprising results' from roadside drug testing: police"; NZ Police, roadside drug driving testing and penalties and outcomes; Land Transport Act 1998, s64. This post is general information, not legal advice; no outcome is guaranteed.