OTTAWA — Canadians are "increasingly likely" to support the legalization or decriminalization of drugs, including marijuana, the public safety minister's top bureaucrat has quietly advised.

It's a message that runs counter to the Conservative government's firm opposition to softer penalties for recreational pot smokers — an issue that has flared up regularly on the federal campaign trail.

Liberal Leader Justin Trudeau proposes legalizing marijuana — selling and taxing it much like alcohol — while the NDP's Tom Mulcair has come out in favour of decriminalizing pot. Trudeau has argued legalization would help shield young people from marijuana by closely regulating a trade now run by criminals.

Conservative Leader Stephen Harper has harshly criticized Trudeau's legalization plan, saying no one believes selling marijuana in stores will better protect children.

In a June briefing note to Public Safety Minister Steven Blaney, deputy minister Francois Guimont said self-reported surveys indicate that Canadians, both...