A group of Canadian doctors called for tougher measures to ban "misleading" cigarette package labels on Tuesday, the same day that a voluntary agreement by tobacco companies to drop the terms "mild" and "light" from cigarette packages came into force.

In November 2006, Imperial Tobacco, Rothmans, Benson & Hedges and JTI-Macdonald announced they would voluntarily phase out the terms on their cigarette packaging in Canada on July 31, 2007.

At the time, Physicians for a Smoke-Free Canada said that the agreement was poorly written and would not be effective.

"As predicted, the companies have not ended the deception," said group president Dr. Atul Kapur. "The tobacco companies have merely replaced the words 'light,' and 'mild' with other marketing terms."

According to the group, the tobacco companies can continue to make changes to the packaging — such as using lighter colours or more white space — that falsely convey differences in strength.

The group says they can also continue to prominently display misleading numbers on packages that falsely convey differences in the amount of compounds inhaled between brands or sub-brands of cigarettes, and that fail to tell consumers how much they are inhaling.

Imperial Tobacco's spokesperson was not immediately available.

"The recent decision of the Supreme Court should give the federal government confidence that it can move meaningfully to remove all these forms of deception," said Kapur.

In June, the Supreme Court of Canada upheld the 1997 Tobacco Act, which severely restricts tobacco companies' right to advertise. The companies had argued that the law infringed on their freedom of expression.

Chief Justice Beverley McLachlin, writing for the court, rejected the companies' contention, and concluded the advertising law's key provisions "are constitutional in their entirety," and "nothing less than a matter of life or death for millions of people who could be affected."

McLachlin also took the companies to task for having a long history of misleading the public in their advertising, and said their ability to send a positive message about a noxious product was impressive.

'Low value'

"The expression at stake — the right to invite consumers to draw an erroneous inference as to the healthfulness of a product that, on the evidence, will almost certainly harm them — is of low value," she wrote.

The law requiring graphic warning labels on cigarettes packages to occupy half the area of the fronts and backs of packages was also upheld.

At the time, the tobacco companies said they would soon resume the limited advertising they are allowed: through direct mail, in places where young people are prohibited and in some adult-oriented magazines.

Meanwhile on Tuesday, the Competition Bureau said it had reached agreements with six other tobacco manufacturers to discontinue the use of the terms light and mild on their cigarette packaging by no later than Dec. 31, 2007.

Those companies are A.D.L. Tobacco, Similar Tobacco, Kretek International, Walking Smoke Distribution, Bastos Du Canada and Abenakie Enterprises/Choice Tobacco.