Murray Hodson More than 90 per cent of motorists in Northland tested for driving under the influence of drugs have illicit substances in their blood, including cannabis and methamphetamine, the region's road policing boss says.

Inspector Murray Hodson said by the start of October, 67 people had been convicted of driving under the influence of drugs and more had been caught since.

"That's a very high number and a real concern," he said. "There are hard drugs being found, which is really worrying, as the harder the drug, the more damaging effect it has on your driving."

Police can drug-test drivers only if they believe they are under the influence. The impairment test entails the driver having an eye assessment, followed by a walk and turn, and one-leg stand test. Drivers who fail the test must have a blood test.


"Anybody stopped on the roads will be breath-tested and if the officer suspects they have been driving under the influence of drugs, they will be tested for that too," said Mr Hodson.