First-time offenders will also lose their licence for a minimum of three months and a maximum of 12 months and could be fined as much as $1200.

The maximum penalty now for the offence is a three-month suspended licence.

A person convicted of a subsequent drug-driving offence could lose his or her licence for up to two years, be fined up to $2400 and imprisoned for a maximum of six months.

Police Minister Jim Cox said drug-driving was an extremely serious road offence.

"People operating a vehicle under the influence of drugs pose a huge risk to not only their own safety, but that of every other road user," he said.

"People taking drugs can have impaired perception and reflexes. Driving in such a condition is extremely dangerous and will not be tolerated by the State Government.

"I am confident these new penalties will send a strong deterrent to people contemplating driving under the influence of drugs."