Jamie Oliver has launched possibly his most daring project to date with a global petition that calls on governments far and wide to provide food education for every child in every school and a push for strident taxes on those who make and promote junk food.

The chef and food advocate, who gained household status 16 years ago as "The Naked Chef", announced his plans to nearly 5000 people at his Food Revolution Live shows at the Sydney Opera House on Sunday. He will present the petition to G20 leaders in Turkey in April.

"It's basic intelligence and logic," he told Fairfax Media of the need for regulations that protect children from diet-related disease. "Australia has an opportunity to fix something really profound and important."

He has, so far, convinced six countries of the need for laws that enable every child to have practical food education in school and aims to get every G20 country on board by harnessing a wave of support around the world.

"I will be really upset and will consider it an utter failure if I don't get over 2 million signatures," he said as he met children from Bondi Public School, which is part of food advocate Stephanie Alexander's healthy schools program.

"This is not a Jamie Oliver thing; this is about being Australian, it's about your community, it's about your street, it's about your kids, it's about your future," he said. "You don't need me to tell you about the science of diet-related disease, the cost on healthcare."

With government and big corporations in his sights, he hopes that one day "hideous and unhealthy" fizzy caffeine drinks and junk food come to be regarded in the same light as tobacco, partly through a proposed 15 per cent tax on fizzy drinks, tax on junk food advertising and no tax on fruit and vegetables.

Or, in well-loved Oliver parlance: "We've got make it harder to get the shit and easier to get the good stuff."