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Criminal & traffic law

Drink/drug driving

Defences to drink/drug driving charges

When might I have a defence to a drink-drug driving charge?

Land Transport Act 1998, s 64(1)-(1B)

  • Refusing a blood test for health reasons – It’s a defence to a charge of refusing to have a blood test if the test would’ve been harmful to your health. You’ll need evidence from a doctor to establish this defence.
  • Taking drugs on doctor’s instructions – It’s a defence to a charge of driving while impaired by drugs if you had a doctor’s prescription for the relevant drug or medicine or a doctor gave it to you, and you followed all the doctor’s instructions.
  • Refusing impairment test because of disability or injury – It’s a defence to a charge of refusing or not doing a drug impairment test if you weren’t able to take the test because of a pre-existing medical condition or disability, or because you were injured in the traffic accident that led to the police asking you to do the test.

Factors that don’t amount to a defence

Land Transport Act 1998, s 64(2)

  • Strict compliance with testing rules not necessary – It’s not a defence that the police didn’t strictly comply with the breath- or blood-alcohol testing rules in your case, so long as there was “reasonable compliance”.
  • Earlier tests irrelevant – If you’re charged with driving with excess breath- or blood-alcohol, it’s not a defence that there was a mistake in any of the earlier tests that the police relied on to require you to have further testing.

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Driving and traffic law

Where to go for more support

Community Law


Your local Community Law Centre can provide free initial legal advice and information.

Applying for a limited licence” (guide)

This Plain English guide, plus template application forms and affidavits, will help you apply for a limited licence. It’s available on the Community Law website – www.communitylaw.org.nz

New Zealand Transport Agency (NZTA)


Phone: 0800 699 000
Email: info@nzta.govt.nz

The NZTA site provides a wide range of driving and road safety information, including on topics covered in this chapter.

You can read and download fact sheets and other publications from their site, or you can order hard copies by contacting them, including their fact-sheet on Legal mobile phone use while driving.


NZ Police

Frequently Asked Questions


The “Driving/road safety” and “Tickets/infringements” section of this webpage have Frequently Asked Questions about traffic fines, speeding, demerit points and where you can pay your fines.

Consumer protection

“Parking, towing and clamping”


This Consumer Protection webpage has information about the law covering tow trucks and wheel-clamping on public and private property, and about unreasonable fees in private car parks.

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