Drivers testing positive for drugs they have not taken could prove problematic for any plans to adopt a roadside drug driving testing scheme in New Zealand.

But experts and advocates say the policy is still worth pursuing to help save lives on New Zealand's roads.

This week, Associate Transport Minister Julie Anne Genter and Minister of Police Stuart Nash called for public consultation on the issue of drug driver testing.

The latest data from the Ministry of Transport shows that drugs were the reason for 21 per cent of fatal crashes in New Zealand in 2017 – ahead of alcohol