The Royal Life Saving Society says it is concerned that a growing number of Australian children do not know how to swim, or lack the skills to keep themselves alive in the water.

It is estimated 20 per cent of children will leave primary school without the ability to swim the length of an Olympic-sized swimming pool.

Royal Life Saving's CEO, Rob Bradley, says there are not enough schools providing swimming lessons to students.

"Some very good programs are offered through local aquatic centres, but it's a very fragmented approach throughout Australia through the education system," he said.

"It should be the responsibility of the Australian Government to ensure that every child in Australia has these vital swimming and safety skills."

Ms Bradley says kids from minorities are more likely to struggle in the water.

"We're seeing big gaps in populations that receive no water safety lessons at all," he said.

"These are from Indigenous communities, many cultural backgrounds, rural and remote communities and people from lower socio-economic families."