Fewer girls and teachers were involved in secondary school sports teams last year, School Sport New Zealand's annual survey has found.
The survey results showed 49 percent of girls represented their school in 2018, down from 50 percent in 2017 and the lowest figure since 2012.
Fifty-six percent of boys played sport for their secondary school, the same figure as the previous year.
Participation rates varied between regions. Nationally, 52 percent of students represented their secondary school last year, but in Wairarapa the rate was 71 percent and in Waitakere it was just 39 percent.
The survey found 31 percent of school teaching staff were involved with a school sport team, the lowest figure since a high of 46 percent in 2000.
School Sport New Zealand chief executive Garry Carnachan said teachers' involvement had been dropping by about one percentage point a year for the last ten years.
He said there were a number of reasons for the decline including the ageing of the teaching workforce and the increasing number of paid jobs in the sports industry.
"A lot of people who would have gone into teaching with a real sporting interest are in other occupations and not going to teaching these days," he said.
However, Mr Carnachan said the decline in teacher involvement did not seem to be having a big impact on students' participation and people in the community were stepping in to coach or manage teams.
School Sport's annual surveys indicated that formal, organised sport suited only about half the students in secondary schools, he said.
"What it says to us is we need to offer a lot of informal opportunities for sport and physical activity, to look at perhaps sport inside the school gate."
That meant involving students in designing their opportunities, rather than assuming what they wanted, he said.
The survey showed netball was the most popular sport in secondary schools last year with 27,139 players, followed by basketball with 26,481, rugby with 25,317 players, and football with 23,513.