Half the state's schoolchildren are finishing their primary education without the ability to swim, with the Royal Life Saving Society fearing this summer's spike in drownings will worsen.
Royal Life Saving NSW's Michael Ilinsky said the 17 drowning deaths recorded in NSW since December 18 was "unprecedented". The death toll includes four toddlers who have drowned in backyard pools. Two children drowned in backyard pools in NSW in the year prior to that.
Mr Ilinsky has warned it may be a problem for summers to come, with evidence that half of an entire generation is growing up without the ability to swim 50 metres of freestyle. The non-swimming figure has increased from about 25 per cent a decade ago.
"We are still getting figures of approximately 50 per cent of kids coming out of primary school without the capacity to swim," he said.
"We have a future generation of children that live in a country that loves the water and there is the potential for a blowout in our drowning figures that we won't see immediately but when they turn 17 and 18 and start driving themselves to aquatic environments and for those that don't have the skill set, it can be lethal."
Mr Ilinksy said the cost and the option of other, non-traditional sports such as rock-climbing and ice skating now offered in school meant swimming was not as widely taken up as it once was.
"The options available at schools are vast and aquatics, swimming and survival used to be a key component, but it's got ... more expensive and it is one of those critical life skills that is becoming tightly squeezed."
Royal Life Saving says hot weather, lack of supervision and risk-taking males have contributed to the spike.
"It's absolutely devastating to think that this Christmas period we've had more children drown in backyard pools than we've had in the last 12 months in NSW," Mr Ilinsky said. "It is unprecedented for such a short period of time to go by and for there to be such a significant number of drowning deaths."
Mr Ilinksy said 75 per cent of backyard drownings were caused by a faulty, or deliberately kept open, pool gate and that parents and carers must remain vigilant with young children when water is around.
"With warm temperatures everyone is flocking to a backyard pool or an aquatic environment, there's the barbecue, the social interactions and other distractions and we all know it takes 60 seconds for a child to be out of your sight and it is too late," he said.
The latest deaths include toddler Vera Peacock who was found unconscious in a backyard pool in Macquarie Fields in Sydney's west on Sunday evening.
The two-year-old girl had been at a family gathering at the home and was rushed to Liverpool Hospital but later died.
Acting Superintendent Mark Brett said police were investigating the circumstances of Vera's death, including whether the pool fence had been left open. He said the toddler had been missing for "a few minutes" before she was found.
"There's a lot of people meeting for the first time for a long time and it's very easy to become distracted," he said. "Our prayers and thoughts go out to the family of the young child. It's very tragic circumstances at a supposedly joyous time of the year."
Police on Monday also recovered the body of a 44-year-old Cooma man after he had gone missing while swimming with family at Lake Eucumbene in the Snowy Mountains on New Year's Day.
Statistics show men account for 80 per cent of all drownings with most of those falling within the 25 to 50 age bracket. The 17 drowning deaths in NSW since December 18 compares with 96 drowning deaths statewide recorded between July 1 2015 and June 30, 2016.