Canada's three major cigarette companies pushed for more advertising leeway Monday as they challenged the Tobacco Act before the Supreme Court of Canada.

The big three -- Imperial Tobacco, JTI Macdonald, and Rothmans, Benson & Hedges -- say current legislation is so vague that it can be interpreted as a total advertising ban.

Simon Potter, a lawyer representing Imperial Tobacco, told the court that the law forbids any ad that could be interpreted as appealing to youth.

However, ads clearly aimed at adults could be "construed" as appealing to youth, something that would be enough to render it illegal.

"To imagine an ad that can't be construed to be appealing to someone who's 17 years old, in my estimation, is impossible," Potter told the court. "The world 'construed' is entirely subjective."

He asked the court to clarify the framework in which the companies could advertise.

"If you ban everything except what is explicitly permitted, care must be taken to actually be clear as to what's permitted," he said.

Potter suggested a model similar to that used for beer advertising. Those spots are cleared by government and industry representatives before they are released.

The tobacco companies are up against Ottawa, six intervening provinces -- Ontario, Quebec, Manitoba, New Brunswick, Saskatchewan and B.C. -- and the Canadian Cancer Society.

Restrictions justified

Lawyer Cynthia Devine, arguing on behalf of the Attorney-General of Manitoba, said the federal Tobacco Act's provisions should be upheld.

"This court has upheld several prohibitions on expression couched in terms less precise," she said.

Devine was referring to laws regulating election campaigns and telephone marketing.

Dominque Jobin, lawyer for the Attorney-General of Quebec, noted that the tobacco industry has previously enjoyed success at getting around past restrictions.

"In order to achieve the purpose of the law, which is to create an effective counterweight to evolving marketing techniques, we have to take a wide approach," she said.

Even if the law does restrict freedom of expression, the restrictions are justified because they help the law achieve its purpose -- sensitize Canadians to the fact that smoking is dangerous, said Julie DesRosiers, representing the Canadian Cancer Society.

She accused the tobacco companies of having a hidden agenda.

"If you look at an advertisement that says straight facts about the product this is allowed under the act. But this is not the type of advertising they want to make. They want to make advertising that could be in some way appealing to young people," she said.

The cancer society said smoking kills 45,000 Canadians annually.

British Columbia took a different tack from the others, arguing that because smokers are addicts, cigarette ads cause harm by leading people to harm their own health.

The Supreme Court usually takes several months to rule once it has heard arguments. 

This isn't the first court fight over tobacco advertising.

The first ban on tobacco advertising was passed by Parliament in 1988 but it was challenged by RJR-MacDonald and struck down by the SCC in 1995.

A narrow majority of the judges said the federal government failed to prove a connection between a ban on advertising and a decline in smoking rates.

The court recommended that Parliament permit information or brand-preference advertising but said ads that promote a smoking lifestyle or target kids should be banned.

The Tobacco Act of 1997 was again challenged by cigarette makers but was upheld by a lower-court judge. However, in 2005, a Quebec Court of Appeal ruled that it is unfair to bar tobacco companies from showing their company names when they sponsor events. Yet, the same court ruled that the brand names cannot be used in those cases.

With files from The Canadian Press