A three-year-old boy has died and a toddler is fighting for his life following separate incidents involving backyard swimming pools in Sydney's south-west, police say.
The boy, who collapsed after swimming at his family's pool in Riverwood about 5.30pm on Sunday, died in hospital.
Two backyard pool incidents in Sydney
A young boy has died and a toddler is in a critical condition following two separate incidents involving backyard swimming pools in Sydney's south-west. (Vision courtesy ABC News 24)
An hour later, a two-year-old boy was pulled unconscious from a backyard swimming pool in Camden South, about 50 kilometres away.
A NSW Police spokeswoman said the first incident occurred at a home on Kentucky Road in Riverwood.
The boy is believed to have been swimming in the above-ground pool while a number of adults were present.
Witnesses told police the boy got out of the pool and walked a short distance before he collapsed. He was unconscious when paramedics arrived.
He was taken to the Sydney Children's Hospital, but died a short time later, the police spokeswoman said.
A post-mortem examination will be conducted this week to determine whether he died from a pre-existing medical condition.
About 6.30pm, emergency services were called to a home on Smart Avenue in Camden South to reports that a two-year-old boy had nearly drowned in a backyard swimming pool.
When paramedics arrived, the toddler was breathing but he was not alert.
He was flown in a critical condition to The Children's Hospital at Westmead, where he remained on Monday morning.
Police are investigating the circumstances surrounding both incidents.