Primary schools will be pushed to provide one hour's "moderate to vigorous" exercise each day in the country's biggest physical education shake-up.
Under the plans, designed to arrest growing obesity, schools could end up offering skate-boarding or even extreme sports to tempt children away from television and computer games and take up exercise.
The changes do not alter the PE curriculum, but will examine ways to integrate an hour of exercise into and around the school day, including before and after school and during other lessons.
But an hour's physical activity in an already crowded school day has been attacked by the head of the primary principals' organisation as "pie in the sky".
The changes come into force as tens of thousands of children start school next week.
They are an extension of the Government's Active Schools programme, which requires a minimum of one hour a week of exercise in primary schools and, for the first time, gives PE the same curriculum priority as maths and English.
Sport and Recreation New Zealand, with the Ministry of Education, is installing a team of regional sports advisers to push schools to provide for one hour each day.
This follows a two-year pilot project which revealed that 96 per cent of primary-age pupils failed to perform 12 fundamental physical activities such as running, jumping and catching. "Where we are headed at the moment is a pretty scary place," Sparc's education manager, Cath Clark, told the Herald.
"There's so much more choice for children, with iPods, Gameboys, PlayStations, television and the rest. We had to say, 'What are we offering children that will attract them to exercise?'."
The plans will try to do away with "boot camp"-style PE lessons and instead concentrate on providing popular opportunities that capture the young imagination.
Ms Clark said that could mean offering mountain-biking, skate-boarding and even extreme sports.
The Sparc study showed just 17 out of 424 children had all 12 fundamental movement skills, and a third of youngsters were overweight or obese.
"I don't believe one New Zealander can be comfortable with these figures," she said. "It's quite frightening and if we want healthy members of society we need this."
But Pat Newman, president of the Principals' Federation, said a crowded curriculum meant schools could barely manage one hour a day for reading. "Let's get real and stop being politically correct - the responsibility for this is with parents and families."
Schools supported increasing the amount of physical education, but the responsibility could not be shoved on to them alone. "The advisers will be of great use, provided they concentrate on the community," said Mr Newman. "Health and fitness gurus are all very well, but they must realise there's much more that schools need to focus on. It's pie-in-the-sky stuff."
Sparc has appointed 17 regional advisers. This figure will rise to 29 by June.
The Education Review Office will measure schools' progress.
Irene Cooper, head of the primary teachers union the NZEI, said an hour a day was an ideal that would be achieved only with creative time management. Physical education also needed to go with healthy eating.
"Together [schools and communities] can achieve this, but we will not have the existing teaching programme dragged down," she said.
Education Minister Steve Maharey said the issue of children's health had to be taken seriously. "We've got a time-bomb on our hands and some time in their lives they will have a hell of a problem unless we act now."
* One third of school-age children are obese or overweight (about 250,000).
* New Zealand is ranked number seven in an OECD league of the world's most obese nations (20.9pc of adult population).
* That figure is expected to rise to 29 per cent by 2011 as today's children grow up.
* About half a million adult New Zealanders are obese - twice as many as 25 years ago.