The revised federal Tobacco Act says only cigarettes with the new series of warnings can be legally sold as a further deterrent to smokers.
In December 2010, Health Minister Leona Aglukkaq ordered studies to strengthen the old regulations that required 50 percent of the front and back of tobacco products to carry warnings and pictures.
The rules now say 75 percent of each side must have one of 16 warnings, and smaller warnings are also printed inside the packages. There are also detail toxic emissions statements on the sides of packs and a Canada-wide telephone number and Internet address for smokers who want help quitting.
Of the images of various diseases associated with smoking, one for bladder cancer shows a swirl of blood in an open toilet bowl.
Also Tuesday, Statistics Canada said 19.9 percent of Canadians, or 5.8 million people above the age of 12, smoked in 2011.
It wasn't clear what retailers would do with their inventories of cigarettes with the previous warnings.
Previous government attempts to make cigarettes unaffordable with high taxes led to a boom in contraband tobacco, much of it sold from Indian reservations.