Schools are looking to skateboarding and surfing to try to reverse declining numbers of both students and teachers taking part in sports.
New data from School Sport NZ shows that high-school boys' participation in sports has slipped from 59 per cent to 55 per cent since the start of this century, and girls' participation has dropped from 55 per cent to 47 per cent.
Most dramatically, teachers involved in sports have plunged from 46 per cent of all secondary school teachers 20 years ago to an all-time low of 29 per cent.
Waitākere College principal Mark Shanahan, who chairs College Sport Auckland, said schools needed to "look at the opportunities to engage kids into the new Olympic sports of skateboarding and surfing" if they no longer play rugby or cricket.
"The non-traditional sports are the ones that kids are moving into," he said.
"Snowboarding sports have boomed in big numbers. Skateboarding and surfing - we have to get kids involved in those things. We have to make sure that we stay relevant.
"All the traditional sports are still at schools, but some schools may struggle to get a coach."
Former Mt Maunganui surfer Lee Ririnui, who won the under-17 surfing championship in 2016 and is now a semi-professional surfer, said sports such as surfing and skateboarding were seen as "cool".
"It's a popularity thing," he said.
"Being at the Mount [Maunganui] College, and keeping in contact with other people in Tauranga, pretty much every second person I know likes to go surfing. It's definitely growing.
"I do know rugby players, but with rugby there's a first and second XV and pretty much that's it now, so there's only really 40-odd from the senior year groups that play it competitively, whereas surfing you can do it every day."
High-school students playing rugby have dropped by a fifth, from 30,621 in the year 2000 to 24,731 last year.
Cricket players have almost halved from 17,794 to 9096.
But Steven Adams' success in US basketball has helped propel basketball numbers up by 53 per cent to 25,072, surpassing rugby as the second-most-popular school sport after netball, which has held steady at 27,000 players.
Other new sports which did not even exist in schools 20 years ago have grown quickly, such as futsal (indoor football), waka ama and Kī o Rahi, a seven-a-side touch game which 3224 high-school students played last year.
Ririnui moved from Mt Maunganui College to do his last three school years at Raglan Area School, which has a surfing academy.
He achieved level 3 of the National Certificate of Educational Achievement (NCEA) in 2018 including physical education credits in surfing, as well as academic subjects.
"It's the only school that does anything similar to that. There are people who come from Christchurch," he said.
"It would be good for the schooling system to embrace sports that are high in popularity. I think it would definitely be beneficial."
Shanahan said new sports and new versions of old sports were "the only way to keep sport going".
He said Waitākere College has not had a First XI cricket team for several years, but has joined up with three other West Auckland schools to create a joint team.
Softball, whose numbers have halved nationally from 4141 players in the year 2000 to 2101 last year, has been reinvigorated with a safer version called "slow pitching".
Shanahan said new teachers, who were reluctant to coach traditional sports which they had not played themselves, were also more likely to take on newer sports.
"I think there have always been teachers keen on surfing," he said.
The School Sport data shows that school sports coordinators are most likely to be aged 46 to 55 (31 per cent). Another 22 per cent are aged 36-45, 21 per cent are aged 26-35, 17 per cent are aged 55-plus, and only 10 per cent are aged 25 or under.