Eighty school swimming pools are disappearing each year as schools sacrifice the expense of water safety to meet an ever-tightening budget.

In 2002, there were 1906 state school swimming pools, but today there are only 1668 - a drop of 12 per cent.

In just three years 37 secondary schools have disposed of their pools, while 201 primary schools have lost theirs.

It is a trend which compounds the uphill struggle to reverse the country's high drowning rate, say water safety groups.

Alan Muir, Water Safety New Zealand executive director, said it had been a concern for some time and if the drop continued, public pools would not be able to keep meeting the shortfall.

"It's symptomatic of the pressures on schools that have to make ends meet, but it's not going to help drive down the statistics at all."

In most cases school boards have been forced into a corner by tight budgets, with the high costs of pool maintenance and compliance being dropped to free cash for other needs.

A small number of disappearing pools can be attributed to the network review, which has seen a number of school closures in recent years.

Chris Haines, president of the School Trustees Association, said there were some things on the curriculum that could not be shut down.

"The cost burden is so great that schools are looking at swimming pools and saying, 'that's just too much and do we really need it?'."

Kevin Moran, an aquatics education expert at the University of Auckland, said his research had shown more than a quarter of primary schools in Auckland had no on-site swimming facilities and 60 per cent had no specific water safety policies.

"There's pressure on the curriculum and what gets squeezed? It's the difficult bits and that includes swimming," he said.

The alternatives for schools include transporting children to public pools, or leaving aquatics education in the hands of parents.

A Water Safety New Zealand survey in 2003 found 42 per cent of children in higher decile (richer) schools learned to swim at private lessons, compared with only 14 per cent of those in lower decile schools.

At Edendale School in Auckland, where the board of trustees has just agreed to keep the swimming pool after consultation with the community, a survey of parents revealed less than half were willing to pay for public pool lessons during school time.

Water Safety NZ figures show the annual drowning toll has dropped 45 per cent since 1984, with education and intervention widely praised for their influence.

But Mr Muir fears the good work could be partly undone if children do not have access to pools and lessons.

The Accident Compensation Corporation this month released a 10-year Drowning Prevention Strategy.