Health Canada is warning people not to use so-called "electronic smoking" products, and has instructed businesses not to promote or sell them until the government has evaluated their safety.
"Persons importing, advertising or selling electronic cigarette products in Canada must stop doing so immediately," Health Canada said in a statement Friday.
This includes electronic cigarettes (dubbed "e-cigarettes"), cigars, cigarillos and pipes, and cartridges of nicotine solutions.
The department said sales, imports and ads for the devices, which vaporize nicotine without burning tobacco, are governed by the Food and Drugs Act and require federal approval, which none has so far received.
"Today we are letting Canadians know that no electronic smoking products have been granted market authorization in Canada," Health Canada spokesman Alastair Sinclair told CBC News.
"Health Canada has developed an action plan which includes notification to all known importers and distributors requesting the immediate cessation of importation, advertisement and sale until the appropriate licensing requirements have been obtained," he added.
The agency suggests Canadians avoid the products, which have been sold in Canada and over the internet, as they "may pose health risks and have not been fully evaluated for safety, quality and efficacy by Health Canada."
Electronic cigarettes look like the real thing, using a battery-powered system that vaporizes and delivers a liquid chemical mixture that may include nicotine, propylene glycol and other chemicals, the department said.
"Although these electronic smoking products may be marketed as a safer alternative to conventional tobacco products and, in some cases, as an aid to quitting smoking, electronic smoking products may pose risks such as nicotine poisoning and addiction," Health Canada said.
In the U.S., Senator Frank R. Lautenberg sent the U.S. Food and Drug Administration a letter Monday asking the agency to ensure e-cigarettes are not sold until they've been studied further.