Testing regimes are improving, allowing police to determine those affected by drugs such as cocaine and methamphetamine.

Those who take prohibited drugs and drive should be aware police have refined a three-stage process of random drug testing, with drivers yielding a positive result in all three stages then fined and losing their licence for three months.

Those with a previous conviction for drug-driving must face court.

Sgt Cameron Roberts says police have improved enforcement methods and have become more proficient at determining those who should be targeted for testing.

And he has warned those who would abuse prescription medication and get behind the wheel that driving while impaired by any drug is an offence.

Drivers need confirmation from their doctors that they are OK to drive while on prescription medication and that they take it in line with their doctors’ directions.

Otherwise, they could find themselves in as much trouble as those who abuse illicit substances.