“Now is the time to move away from a system that has, for decades, been focused on the prohibition of cannabis into a regulated legal market,” Ms. McLellan said at a news conference.

Mr. Trudeau has promised to introduce new laws by the spring.

Among other things, the panel suggested that the coming Canadian rules for cigarette packages, which are being contested by the tobacco industry, also be adopted for marijuana. They will require plain packages without logos or slogans, and with standardized designs and fonts. The panel also recommended mirroring current rules on tobacco advertising, which essentially ban it.

Sales, the panel said, should be handled through special stores and not, as the province of Ontario had hoped, through government liquor stores. And the minimum buying age, it said, should be at least 18 or match provincial rules for alcohol.

It noted that marijuana stores, which have been popping up in Canadian cities in anticipation of Mr. Trudeau’s efforts to fulfill his election promise, are clearly illegal, suggesting that they are unlikely to be part of a new system.

Over all, the panel acknowledged that its system would be even tougher than current Canadian limits on alcohol and cigarettes, which are themselves severe by the standards of many other countries. But, the report said, that simply reflects the need to do more about alcohol and tobacco.