The young girl died after an incident at the Belconnen pool. Initial reports suggested the girl was three-years-old, ACT Police confirmed on Sunday she was born in 2010 but had not yet celebrated her third birthday. A post-mortem will take place on Monday.

An ambulance was called to CISAC on Eastern Valley Way in Bruce around 11.20am on Saturday, with police called to Calvary Hospital an hour later, after the girl had died.

Police said the girl did not die at the pool, but it was unclear on Saturday night if she died on the way to the hospital or after she arrived.

At the scene on Saturday, Harry Konstantinou of The Club Group told Channel Ten News the young girl’s father initially refused help from lifesaving officials before they intervened, performed CPR and called an Ambulance.

"Witnesses say that the father was forcing the girl to swim when she wasn't interested in swimming. I'm not sure at what stage she passed out but she was limp when the lifeguards walked over and she was in her father's hands just on the grand stand on the bleachers," he said.

The ambulance service would not provide any information about the incident, referring all questions to police.

Police have not revealed details of the circumstances surrounding the girl's death but said they did not believe it was suspicious.

However, the Sunday Canberra Times understands she died of either drowning or a medical condition, and evidence was being prepared for the coroner.

The pool was closed on Saturday afternoon as ACT police detectives investigated the circumstances surrounding the death and forensic officers conducted an examination of the scene, removing a number of bags.

Swimmers arriving at the centre were seen being turned away at the entrance.

Police are preparing a brief for the coroner, and have asked for anyone who was at the pool and who might be able to help with their investigations to contact Crime Stoppers on 1800 333 000 or via www.act.crimestoppers.com.au.

The pool management declined to comment, saying it could not disclose any information.

The pool advertises a strict policy that an adult must be in the pool and within an arm's reach of children under the age of six, and was the first pool in Canberra to launch the Royal Life Saving Society's 'Keep Watch' program, which has various policies for adult supervision of children up to the age of 14.