New cigarette packages featuring graphic photos of a cancer-stricken woman and diseased body parts could help more smokers butt out for good, according to a health psychology expert.

Although the new warnings may not be significantly more graphic than current ones, keeping the images fresh can be a powerful tool in the battle against smoking, according to the University of Waterloo's Geoffrey Fong.

"I think there's going to be increased knowledge about the harms of tobacco use, and greater potential motivation to quit," said Fong, who is the head of Waterloo's University Health Psychology Lab.

Tobacco companies have until March 21 to ensure that their products are being manufactured with large warnings that cover three-quarters of each cigarette package.

And by June 19, the government wants retailers to be fully compliant with the new rules, ensuring that all cigarette packages on store shelves carry the new labels.

Fong said that studies completed around the world have "again and again" found that refreshing smoking warnings works, because it keeps the images fresh in the public.

Canada first introduced warning labels in 2000 featuring disturbing images, but since then, cigarette packages have remained unchanged.

"As anyone in advertising or communications knows, when you have exactly the same message to the public for 10 years, you've got to make a change," Fong told CTV's Power Play.

In some ways, said Fong, the new warnings could be more dramatic than their predecessors, because they touch on the impact that smoking-related diseases have on quality of life.

"That's what you're seeing in a lot of these warnings," he said.

One warning says that strokes can leave "you helpless," which provides the public with more awareness of the real-world consequences of smoking, said Fong.

Fong, who is also senior investigator with the Ontario Institute for Cancer Research, has found in his research that the majority of smokers are concerned about their tobacco use, and they want help to quit.

While he said some hardcore smokers won't be affected by the warning labels, many others will be.

"There are a lot of people in the fuzzy middle that are concerned about what they should do, and every day is a new day for trying to figure out if they are going to quit on that day."

Earlier on Tuesday, Health Minister Leona Aglukkaq said the announcement of the new deadlines was proof of the government's resolve to inform Canadians about the dangers of smoking.

Some of the new labels will also include images of Barb Tarbox, an Edmonton woman who died of lung cancer at the age of 42. Tarbox was a well-known anti-tobacco crusader at the time of her death in 2003.

With files from The Canadian Press