Health experts have called on schools and parents to take a more pro-active role in the long-term health of Australia's teenagers after a new survey found a quarter of the country's adolescents were overweight or obese.

A report by the Cancer Council and National Heart Foundation revealed teens were spending too much time in front of the television with 58 per cent of students having at least three televisions in their home and 40 per cent with video games in their bedrooms.

In addition, more than three-quarters of teenagers were spending more than two hours in front of computers, laptops, tablets, video games and televisions every school day.

Chair of the Cancer Council's Public Health Committee Craig Sinclair said there was a marginal improvement in their physical activity levels, but any modest benefits were undone by the increased screen time.

"That's increased from 71 per cent in 2010 to 77 per cent in 2013," Mr Sinclair said.

"The vast majority of adolescents, you know, 82 per cent, are not engaging in more than 60 minutes of physical activity per day as is what is recommended.

"As a parent myself I know the challenges of managing electronic devices in the home and it's not easy."

He said schools needed to encourage physical activity while local and state governments needed to ensure adequate recreational facilities for teenagers such as cycle tracks or skate parks.

"Already, a quarter of male secondary students are overweight or obese, for female students, a fifth fall into this group," he said.

"And as they carry this extra weight into adult life, their risk of chronic diseases and cancer increases.

"We certainly have very strong evidence of a direct link between obesity and a range of cancers particularly breast cancer in post-menopausal women, bowel cancer and kidney cancer.

"So it is critically important that we minimise the risk of future adult Australians from getting to the point where they are managing excessive weight."

However, finding a way to get teenagers to look 30 years into the future and consider a health condition they might develop is not an easy task, Mr Sinclair said.

"What we can do and what the evidence is clearly showing is that if we create environments where it's easy for teenagers to be active then they are very likely to be engaged in that activity and we've certainly seen that in other health areas.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 4 minutes 4 seconds 4 m 4 s Teens urged to peel themselves away from screens Download 7.5 MB

"If you look at tobacco control in particular, there is a decreasing prevalence of smoking in this population and that's largely because of not telling them not to smoke - we don't advertise to them directly, but more importantly because we've created environments where it is not conducive for them wanting to smoke," he said.

Jo Salmon from Deakin University's Centre for Physical Activity and Nutrition Research said Australia needed a physical activity strategy.

"They could be walking and cycling to school more, we could have much more activity at the school, on weekends and even standing strategies in classrooms is something that we're looking at in our research at the moment," Ms Salmon said.

"We're looking at strategies in schools to get adolescents to stand up and engage in more active curriculum throughout the day. It helps them not only to increase their energy expenditure but also to focus and pay attention in class.

There is a suggestion urban planning could also play a huge role.

"Parents are concerned about safety and traffic safety so we need to build streets that support adolescents cycling safely to school," she said.