The new policy also proposes barring chocolates, chips and fatty foods from tuck shops.
Chief Minister Katy Gallagher believes there will be strong public support for a proposal to introduce a traffic-light food rating system for school activities and events in the ACT.
Education and Training Minister Joy Burch opened the draft policy for public consultation on Monday.
The draft policy proposes a traffic-light system ranking food and drinks at ACT public school activities and events.
Food and drinks which should not be on the menu would be flagged as red, while those that should be consumed in moderation would be classified as amber and healthy options would be rated as green.
Although Ms Gallagher believed there would be broad public support for the policy, she said it was appropriate it was opened to the community for consultation.
"We know from all the research, it's well understood by parents and it's easy to implement at the school level," she said.
"I'd have it in today if it was my choice but we've got to have that process with schools, work out how they're going to use it and also take feedback. This is a step in the right direction so hopefully we don't need too many super-bariatric (hospital) rooms in the future."
A blanket ban on vending machines is among several tough new measures for ACT schools being considered under the draft policy which is open for public comment until October.
About one in four Canberra children are obese or overweight.
The ACT government wants to introduce a ban on the sale of soft drinks in school canteens by the end of the year and the new policy also proposes barring chocolates, chips and fatty foods from tuck shops, and prohibiting junk food as student rewards.