Health advocates have warned e-cigarettes are being taken up by young people rather than helping long-term smokers to quit.

New restrictions adopted in Queensland have made it illegal to sell e-cigarettes to people under the age of 18.

Cancer Council policy and advocacy director Paul Grogan said Queensland was leading the way in recognising the potential harm of e-cigarettes.

Mr Grogan said precautions to protect the community's health had to be a priority.

"There's a lot of confusion out there around electronic cigarettes," he said.

"When you say that they are healthier than tobacco cigarettes it's more a case that they're probably less harmful, but we really don't know to what extent they could be harmful."

An electronic cigarette, or e-cigarette, is a device that heats liquid to produce a vapour that is drawn into the lungs.

"The e-cigarettes that are for sale claim to have no nicotine in them but when they are analysed independently, quite often it turns out that they do [contain nicotine]," Mr Grogan said.

The Cancer Council wass concerned that a large amount of misinformation was being generated about electronic cigarettes.

"It's a regulatory vacuum and we are really concerned about the overall potential harms to population health," Mr Grogan said.

"Because they're so poorly regulated, you've basically got a lot of young people now buying products in a totally unregulated environment.

"We know there are hydrocarbons and glycerol and potentially harmful chemicals, but we really don't know to what extent."

Popular among adolescents

Without long term evidence on the effect of e-cigarettes on health, the Cancer Council urged people to be cautious.

"We see some serious risks here and we ought to err on the side of caution... particularly to protect our young people," Mr Grogan said.

"People are mixing these up themselves... I can't think of any parent who would want to think of their adolescent kids cooking this stuff up and sucking it straight into their lungs.

"This was a problem we didn't have a number of years ago. It's a real frustration for those of us working in public health because it wasn't even on the horizon a number of years back.

"It's something we're just better off without."

Mr Grogan said it was difficult to believe that e-cigarettes could be helping people to decrease their nicotine use.

"We've seen a very significant increase in the use of electronic cigarettes particularly among young adults and older adolescents," he said.

"These things are a device that are being promoted to reduce the harms of tobacco smoke for long-term cigarette smokers, but it seems the major take-up is among people who aren't long-term addicted tobacco smokers."