Stoned drivers will face drug tests if suspected of being high behind the wheel from Sunday.
More than 200 police officers have been specially trained to conduct roadside tests on drivers suspected of being impaired by illicit or prescribed drugs.
If a driver had difficulty with basic coordination, such as walking and turning, and standing on one leg while counting down numbers, or showed a change in eye pupil size, they would be required to submit a blood test to test for illegal drugs or prescription medicines.
This is one of 20 new transport rules coming into effect Sunday – there is also a ban on using handheld mobile phones while driving and a requirement for riders of post-1979 motorbikes and mopeds to use headlights at all times.
People wearing seat-belts incorrectly and vehicles being towed at more than the new speed limit of 50 kilometres per hour will also be targeted, national road police manager Superintendent Paula Rose told The New Zealand Herald.
National Organisation for the Reform of Marijuana Laws Auckland’s coordinator Chris Fowlie has said the organisation supported the changes and advocated “responsible cannabis use”, and driving while affected by marijuana did not meet that standard.
However, Mr Fowlie has said he feared the new law would make it easier for police officers to single out stereotypical cannabis users.