9News understands the five-year-old boy was submerged underwater for 4 minutes in a pool at Sydney Olympic Park Aquatic Centre.
CPR was carried out for quarter-hour by an off-duty paramedic and nurse in addition to lifeguards.
"First responders on the Aquatic Centre did an important job with their resuscitation, managing to get the affected person respiration once more," NSW Ambulance Inspector Fortunate Phrachanh stated.
"It was important to stabilise the affected person and get him to hospital care as shortly as potential."
"We're hoping the perfect efforts of all responders end in a optimistic end result."
The boy was rushed to the Youngsters's Hospital at Westmead in a important situation.