The company said Wednesday it believes current regulations, including the existing 50 per cent sized health warnings, provide sufficient information to consumers.
Imperial Tobacco spokesman John Clayton said the government should instead be cracking down on the illegal tobacco market where packages have no health labels whatsoever.
"In choosing to further regulate the legal and already heavily regulated industry, it is clear that the federal government is avoiding the country's No. 1 tobacco problem — the illegal tobacco market," Clayton said in a statement.
The government approved the increase in the size of graphic health warnings in September 2011. All tobacco packaging in Canada must comply with the new regulations by June 19.
Imperial contends that increasing the size of the warnings infringes on its ability to communicate and violates the federal Charter of Rights and Freedoms.
''Does anyone seriously believe that Canadians don't already know the risk of smoking?" Clayton asked. ''Increasing the size of the warning from 50 to 75 per cent will not lead to any measurable change to public awareness.''
The anti-tobacco lobby begs to differ.
Rob Cunningham of the Canadian Cancer Society cited the increased warnings of recent years as one of several factors that have driven down youth-smoking rates.
He also said other countries — such as Australia and Uruguay — have even larger labels than the one planned in Canada.
"These (labels) are very efficient at reducing smoking," said Cunningham, a senior policy analyst for the organization.
"If they didn't work the tobacco industry would not be trying to strike them down."