SYDNEY, Australia — More than seven months have passed since Australia imposed one of the world’s toughest laws for tobacco warning labels, swapping iconic packaging for graphic images of mouth ulcers, cancerous lungs and gangrenous limbs.

And though experts say it is too soon to know what impact the law has had on tobacco use, one thing is certain: Smokers think the cigarettes taste off. Complaints started to roll in about the flavor of cigarettes almost immediately after the law went into effect on Dec. 1. That could mean a lot for health advocates’ efforts to prevent smoking.

“Of course there was no reformulation of the product,” the Australian health minister, Tanya Plibersek, said in an interview. “It was just that people being confronted with the ugly packaging made the psychological leap to disgusting taste.”

She said it would be a number of years before she could say that the effort decreased smoking rates and improved residents’ health. “But the best short-term indication I have that it’s working is the flood of calls we had in the days after the introduction of plain packaging accusing the government of changing the taste of cigarettes,” Ms. Plibersek said.