The Liberals are looking into mandatory drug testing in workplaces in connection with cannabis legalization and say it's possible for certain job sectors.

MP Bill Blair, the government's point person on the file, told CBC Radio's The House on Thursday that safety-sensitive positions — like pilots — could potentially be subjected to mandatory testing in the future.

"We examined very closely what we could do as far as testing when there was a bona fide safety requirement," he told host Chris Hall.

"In those very limited circumstances, it's possible."

Officials, labour groups and employers have been split on whether to implement mandatory testing.

There are currently no federal labour rules about drug and alcohol testing outside the military and successive governments from the late 1980s have stayed away from the issue.

However, the decision to introduce legislation to legalize cannabis, which the government hopes to have in place this summer, has placed pressure on the government to establish national rules for workplace drug testing.

The Government's Representative in the Senate Peter Harder says he will have the Senate sit as long as it takes to pass both government cannabis bills. 1:08

But there are privacy and constitutional complications, many of which arose during examinations of Bill C-46's proposals for tackling drug impaired driving.

"Blanket random testing is not allowed," Blair said.

Despite Blair's comments, it's that mandatory, random testing some groups are calling for.

"It's been proven to work," Derrick Hynes, president of Federally Regulated Employers Transportation and Communications, argued.

"It results in a change in behaviour, which is precisely what you're looking for. You're not looking for a punitive measure."

Hynes said he thinks there can be a balance between privacy rights and safety, adding he hopes the two cannabis bills can be amended to include a section on mandatory drug testing.

Regardless of whether it's included in this round of legislation, he said he'll continue to push for it.

While it appears there's no plan to include amendments dealing with mandatory testing in Bill C-45 — the main piece of cannabis legislation — Blair said it will be an ongoing conversation after the legislation is in place.

"It is part of an important and complex discussion."