Children's height and weight would be measured every two years unless parents opt out as part of an ambitious proposal to tackle Australia's obesity epidemic.

The proposal, made by the Global Obesity Centre (GLOBE) at Deakin University to a Senate committee examining the issue, argues the data could map childhood obesity around Australia to better target where the problem is at its worse.

The prevalence of overweight and obese young Australians aged 5 to 17 was 27 per cent in 2014/15, according to the Australian Health Survey.

But GLOBE's Steven Allender said the rate of obesity was likely higher.

"The information we have is really quite inaccurate," Professor Allender said.

"We've got millions of children that are suffering from something that will affect the rest of their lives and we have no real understanding of the size of that problem.

"The second point is that there will be areas, groups, communities in Australia that are actually doing really well and their kids' health is good and improving, and we don't know where they are so we can't work out why that is."

The proposal would likely create unease among parents, with one advocacy group saying measuring and weighing children could impact their mental health.

"As a parent, I am anxious to know how children will be weighed and measured," said executive director of The Parenthood, Alys Gagnon.

"I would be anxious to know if it was being done in a healthy, positive way."

Professor Allender acknowledged such concerns but said steps would be taken to reduce any negative impact on children.

More than a quarter of all school-age Australian children are overweight or obese. ( Flickr: Kiril Pipo )

Primary schools would be the "logical place" to take measurements, he said, but trained clinicians instead of teachers would take the measurements and children would not see the results to avoid comparisons.

Names would not be recorded to ensure there are no breaches of privacy.

Professor Allender said an opt-out approach, rather than an opt-in, was necessary to ensure high rates of participation.

"Nobody's being forced to do anything, it's still an active decision," Professor Allender said.

Professor Allender said his submission was based on a model that was working in the United Kingdom and many in the United States.

The submission also calls for greater restrictions on junk food advertising and a 20 per cent price hike on sugary drinks.

"We're creating environments for our kids where it's harder and harder to be active," Professor Allender said.

"Our kids live in an environment that's saturated in junk food marketing."

Federal Health Minister Greg Hunt said in a statement he would refer GLOBE's proposal to the Australian Health Ministers' Advisory Council to consider.

"The primary responsibility for children's health rests with parents and the states who run the schools," Mr Hunt said.

"The importance of exercise and good eating for kids cannot be underestimated in giving them a lifelong platform to good health."

The Select Committee into the obesity epidemic will hold public hearings in Sydney and Melbourne in August.