Royal Life Saving Australia has released data showing a 25 per cent average drop in enrolments across the country for seven to 12-year-olds.

The figures are most stark in metropolitan Sydney where enrolments for 10 to 12-year-olds are down more than 50 per cent and the average enrolment drop is 41 per cent.

"Royal Life Saving is concerned that COVID-19 may create a generation of non-swimmers, who will never be safe around water," Royal Life Saving chief executive Justin Scarr said.

"Parents should be reminded that learning to swim is not only a partial vaccine against drowning, it boosts a lifelong love of swimming for fun, health and fitness."

Queensland swimming enrolments are down 13 per cent in metropolitan areas and 17 per cent in the regions.

The data excludes Victoria where strict restrictions have prevented swimming pool attendance for months.

Enrolment figures were collected from Royal Life Saving's partner organisations who run aquatic centres, such as YMCA and Belgravia Leisure.

Mr Scarr said it's the wrong time to quit swimming lessons.

"If a seven, eight or nine-year-old child can't yet swim 50 metres and tread water for two minutes then they should be in swimming and water safety lessons," he said.

If cost is a barrier, he encouraged parents to investigate government sport vouchers, enrol their child in subsidised holiday programs or ask grandparents to gift swim lessons for birthdays or Christmas.

Royal Life Saving wants Australian parents to assess their childrens' swimming ability against the national benchmark for their age.

The benchmark states every Australian child by age six should be able to swim continuously for at least five metres, submerge, move through an obstacle and identify people and actions to help in an emergency.

By age 12, they should be able to swim continuously for at least 50 metres and tread water for two minutes. They should be able to rescue a person and perform a survival sequence wearing clothes.

Australian Associated Press