Conservative Leader Stephen Harper expressed his vehement opposition to marijuana once again, calling it "infinitely worse" than tobacco at a campaign stop in Montreal on Saturday.

"Tobacco is a product that does a lot of damage. Marijuana is infinitely worse and it's something that we do not want to encourage," Harper said.

He made the remarks in response to a reporter's question about why he was so bothered by marijuana, given that tobacco and alcohol are regulated and many use pot legally for medicinal purposes.

"There's just overwhelming and growing scientific and medical evidence about the bad long-term effects of marijuana," he said, not providing any examples.

He went on to compare his party's approach to the tobacco control strategy.

"We've spent a couple of generations trying to reduce the usage of tobacco in Canada with a lot of success."

Pot came up in second French debate

Marijuana has been a wedge issue throughout the campaign, with the Liberals in favour of legalization and regulation and the NDP favouring decriminalization, rather than legalization.

During Saturday's campaign stop, Harper reiterated that he will retain tough drug laws, which he says are meant to target traffickers, who profit off "destroying people's health."

Campaign 2015: marijuana1:30

Harper clashed with Liberal Leader Justin Trudeau over the issue during Friday's second French-language debate, challenging him on his position, as he has done in the past.

"If we sell marijuana in stores like alcohol and tobacco, that will protect our kids? No one believes that," Harper said.

"The reality is that we have kids who find it easier to buy marijuana than cigarettes and beer," Trudeau responded. 

"If a young person buys marijuana, it's because he had contact directly with a criminal. We will continue to control marijuana like cigarettes and alcohol, not to sell them in corner stores."

Tories link pot with mental health issues

Harper's "infinitely worse" comments received decidedly mixed reactions online, with many bringing up the deaths caused by tobacco and alcohol.

The Conservatives often link marijuana use to increased risks of mental health issues, such as psychosis and schizophrenia, but medical research on that is divided.

Health Canada put out an anti-marijuana ad campaign late last year — which was repeated shortly before the start of the election campaign — that warned pot was responsible for lower IQs. That statement derived from two studies whose conclusions have since been challenged.

In August, Harper claimed a majority of Canadians agree with him on his opposition to pot legalization and promised the RCMP an extra $4.5 million a year to crack down on drug labs and marijuana grow-ops.

According to the latest findings of Vote Compass, CBC's voter-engagement survey, a majority of Canadians are in favour of either decriminalizing or legalizing personal marijuana use — including voters who identify as Conservatives.

With files from The Canadian Press