AN AUSTRALIAN study debunking the myth that cigarettes keep weight down is a further warning about the risks of smoking, anti-smoking campaigners have claimed.

The study, by a research team from the University of New South Wales and the University of Melbourne, found people do not shed fat simply because they smoked.

The research found smokers lost muscle mass, which gave them the appearance of being thinner, but the fat instead was stored around their vital organs.

Mice were studied over seven weeks, with half exposed to smoke from four cigarettes a day for six days a week while the other half smoke free.

Mice on the smoke diet ate about 23 per cent less but their fat mass kept to similar levels.

Quit executive director Fiona Sharkie said today the study was a further warning to smokers they were endangering their health.

It also blew their perception they were burning fat and staying thinner or losing weight, she said.

"If you lose muscle it looks like you are losing more weight," Ms Sharkie said.

"It gives the appearance you are looking skinnier, but you are still storing the fat, which is not obviously a good thing.

"We're debunking that myth as well with these findings."

She said the fat would tend to gather around a smoker's girth and torso, adding to the adverse effects on their health.

"That's around the liver, lungs, heart ... and the stomach as well," she said.