In a statement released in Ottawa, Health Minister Leona Aglukkaq said the new and larger warnings will also be printed on the inside of tobacco product packages.
The new packaging law requires 75 percent of the front and back of cigarette and small cigar packages to carry the warning in English and French along with a toll-free telephone number for smokers who want help quitting.
The move also puts pressure on store owners.
"Retailers now have until June 18, 2012, to sell their inventory displaying the old health warnings," the department said. "As of June 19, 2012, only packages of cigarettes and little cigars that display the new health warnings can be legally sold at retail."
The new warnings can be seen at www.hc-sc.gc.ca/hc-ps/tobac-tabac/legislation/label-etiquette/cigarette-eng.php.
This week, U.S. tobacco companies lost an appeal that the warning messages restrict their freedom of speech.