Police are sending staff to Australia to investigate whether New Zealand should begin saliva testing drivers for drugs.
The Transport Ministry is recommending police begin random roadside saliva testing.
Although the minister responsible for road safety Julie Anne Genter says saliva tests are expensive, intrusive and that the current method of detecting drugged drivers works well.
At present, police carry out a roadside impairment test - and motorists are blood tested if they fail.
Last week, Police Minister Stuart Nash said the police preferred the current method of detecting drugged drivers over saliva testing.
But Police Commissioner Mike Bush said staff would now head to Australia, where some states did saliva test drivers for drugs, to see "if there's a better way".
"We want to know how best to approach it, obviously we think it is a matter that needs to be addressed and we want to work, and provide advice, on what might be the best way," he said.