The former world champion said children were protected from playing with knives, matches and poisons, but he believed easy access to high-fat, high-sugar and high-salt food was just as dangerous.

''There is a moral imbalance,'' he said.

Mr de Castella is also reshaping his SmartStart for Kids program to target morbidly obese children in the ACT, hopeful that he can secure both government and private funding for its expansion.

The ACT government last year stripped the previously school-based program of about $250,000 a year in funding, forcing a dramatic paring back, including a reduction in staff.

He had a proposal for new funding with the ACT government to provide an intensive program over six months for morbidly obese children, those above the 97 percentile, who could be referred by health professionals. The program would incorporate the whole family, teaching them how to shop and eat healthily and how to be active.

''These are kids who are 75, 80 kilos and they're eight, nine, 10, 11 years old,'' he said. ''Their circumstances take a lot longer to fix.''

Health Minister Katy Gallagher said on Friday she was trying to find funding for the reworked program. As for banning junk foods in canteen, she issued a short statement.

''The ACT government has set this out as priority in Towards Zero Growth - Healthy Weight Action Plan and the government will be making some announcements on this in the near future,'' she said.

Mr de Castella said government schools, especially, had a duty of care to provide a safe environment for students, something that was compromised by having junk food and soft drink readily available.

''Young kids don't have the maturity to resist temptation, so making those kinds of things is really unfair and is not creating a safe environment for our kids to grow and learn,'' he said.

Items that would be off the menu in canteens would be those classed as ''red foods'' under the federal government's national healthy school canteens program such as chips, soft drink, doughnuts, pies, lollies and ice-creams.

Mr de Castella made his call at the Garran Primary School, which eliminated all red foods from its canteen last year. It offers portion-controlled snacks such as fruit and vegetables, cheese and biscuits and nachos and has been recognised for its efforts by Nutrition Australia.

He said the argument that canteens lost money when they took junk food off the menu was not strong enough to justify selling foods that compromised children's health.

''You're better off not having a canteen,'' he said.

Garran Primary acting principal Robert Maccioni said the canteen basically broke even and the children had responded ''extremely well'' to the new menu, organised by canteen manager Viva Price.

''The canteen lines are always busy. With children, they eat what is available and eventually they come around,'' he said. ''We also have a very supportive community here and they've backed it up as well.''

Mr de Castella also showed on Friday how much sugar was in a 600-millilitre bottle of soft drink - 64 grams. And how much oil was in a 45-gram packet of chips - 15.7 grams. ''You would never sit down and eat that much sugar in one go or eat that much oil in one go, it'd make you sick. But here we are with kids consuming that in an environment which is supposed to help them grow and develop,'' he said.

Mr de Castella said SmartStart for Kids has survived on small grants since the funding cut last year, but it wasn't enough to continue. He called on the public to help fund the program, which was unlikely to be fully funded by the government.

''We're a tax-deductible health promotion charity, so every donation over $2 is tax deductible,'' he said.

More details are at smartstartforkids.org.au