The Manitoba government is set to introduce legislation to help police crack down on drivers who are high on marijuana.

Justice Minister Heather Stefanson says the bill, expected Thursday, will also include measures dealing with health and safety concerns stemming from the expected federal legalization of pot.

Stefanson hasn't provide details in advance of the bill's presentation, but says the aim is to have checks and balances for when marijuana becomes legal.

She says technology that would let police officers test drivers for pot impairment is still being developed, and the bill will propose different tools for law enforcement.

One in 10 drivers tested had drugs in their system

Stefanson says she's concerned by a survey from Manitoba Public Insurance that said one in 10 drivers who took part in a voluntary test had drugs in their system.

More than half of those with drugs in their system tested positive for marijuana, while cocaine came in second.

"We're taking a proactive approach here to ensure that when that (federal) legislation does come forward, that we already have some checks and balances in place to ensure the safety and health of all Manitobans," Stefanson said Wednesday.

Other details concerning legalized pot in Manitoba, such as where it would be sold, have yet to be worked out, she added.

"We have to wait for the federal legislation to come out."

The Manitoba Public Insurance test involved breath and saliva samples collected last fall from 1,230 drivers. MPI said 124 tested positive for some form of drug. More than one in five of those had more than one drug in their system.

The data did not indicate whether the drivers had enough in their system to be impaired.

Only 2.4 per cent of the drivers had alcohol in their system, MPI said.

"The low incidence of alcohol presence suggests that most Manitoba drivers are making the responsible decision to not drive after drinking," Ward Keith, an MPI vice-president, said in a written statement.

"At 10 per cent, the prevalence of drugs in the tested drivers is significantly more common and extremely concerning."