They flock to the playground to shoot hoops, build cubby houses out of old branches and chat with friends.

A radical overhaul of the school timetable two years ago means that students now have six breaks during the day - four that last for 10 minutes and two 45-minute breaks.

The initiative is inspired by standard practice in Finland, where it's mandatory for students to take a 15-minute break every hour.

Leading Finnish education expert Pasi Sahlberg has called on Australian schools to follow in Finland's - and Harkaway's - footsteps and give students more time to play.

"This is the children's right," he told an Australian Council for Educational Leaders event in Melbourne last week.

"Educators are really worried about how little time children and young people have to do their own thing in school."

Research has found that outdoor play is linked to healthier and happier children.

This in turn leads to better grades, according to Dr Sahlberg, a former director-general of education in Finland who's now a professor at the University of Helsinki and Arizona State University.

"When they have enough time to play outside their test scores go up," he said.

Australian students are spending significantly more time in the classroom than their overseas peers. But it's not improving their performance in international tests or NAPLAN results.

Australian students receive 11,000 hours of compulsory instruction over the 11 years from prep to year 10.

Finnish students, who outperform Australian students, receive 6327 hours over nine years.

Harkaway Primary School leading teacher Simone Randle said the benefits of outdoor play rubbed off in the classroom.

Students are more focussed and less fidgety when they return to class after the breaks, she said.

"Kids love the fact that they can get out and have a bit of a run," Ms Randle said.

"It's a quick 10-minute break, then they know they're back in for work. They come in and are ready for learning, their minds are switched on and ready to go."

Principal Leigh Johnson said the introduction of regular breaks at the south-east Melbourne school had improved students' behaviour, and helped boost their literacy and numeracy skills.

Parents have embraced the change, he said.

"It just makes sense," he said. "They [parents] get up and go for a coffee at work. It seems organic from the parents' perspective."

Grade 6 student Asha Gallard said the regular breaks had improved her concentration in class.

"I used to get fidgety and start daydreaming," the 12-year-old said.

"A lot of us are more focussed now. The breaks in the afternoon are really good because we have been in school for a long period of time."

Her classmate Will Jamsen enjoys choosing how he spends the time. He often plays basketball during the breaks.

"It's helped me out a lot," he said.

"It refreshes my brain."

Dr Sahlberg had some other words of advice for Australia's education system.

He called on schools to celebrate failure - an initiative Ivanhoe Girls Grammar recently adopted as part of its Failure Week.

Dr Sahlberg stressed the importance of equity and urged parents to make time for their children to play.

Education systems fail to improve when they are "addicted to reform", competitive and use student tests as a key measure of accountability, he said.

The best education systems have schools that co-operate with each other, allocate their resources fairly and value all subjects.

"If we we are just focused on reading, writing, maths and science, that's an invitation for inequitable outcomes," he said.