A US study has found vaping teens are at greater risk of smoking 'real' tobacco cigarettes more often, raising the concern of Cancer Council Australia.

Vaping threatens to undo the hard work done to de-normalise tobacco smoking among teens in Australia, warns Cancer Council Australia.

New research has again raised fears that e-cigarette use among high school students puts them at risk of higher levels of tobacco smoking.

A US study published in medical journal JAMA found adolescents who vaped often were more likely to go on to smoke real cigarettes more often.

Cancer Council Australia says the findings are consistent with previous studies that have shown vaping is a potential pathway to combustible tobacco smoking.

Paul Grogen, who works on the Cancer Council's policy advisory board, says the study highlights the importance of protecting the outstanding job done to reduce the prevalence of teen smoking in Australia.

"We have a lot to protect here," Mr Grogen said.

The study also shows why the tobacco industry is the "biggest investor in the e-cigarette industry in the world," Mr Grogen said.

Researchers at the University of Southern California surveyed 3000 Year 10 students, average age of 15.5, about their smoking habits and found that six months after the first survey those who vaped more often were more likely to go on to smoke tobacco cigarettes more often.

And those cigarettes were more likely to be stronger.

According to the research, 37 per cent of the students reported e-cigarette vaping.

At follow-up, smoking frequency was "proportionately greater" among the vaping students.

"The transition from vaping to smoking may warrant particular attention in tobacco control policy," the authors wrote.

Mr Grogen agrees and says while vaping is less harmful than tobacco smoking, there is still plenty of evidence that shows it's not harmless.

"Why would you want your adolescents or anyone of any age for no apparent benefit mixing up these products and then inhaling them directly into their lungs."

"We need to look at e-cigarette use in the context of broader population health risk as well as part of the debate around whether or not they (e-cigarettes) are an effective way to reduce smoking in older heavy smokers," he said.