The girl, who cannot be named, was found lying on the bottom of the pool by her father on the afternoon of September 26, 2010 with her bike still tangled in her laces.

"The bike was still attached when I pulled her out," the girl's father told the inquest into her death. "It was all a bit of a blur."

In his opening address to the inquest, counsel assisting the coroner, Ian Fraser, said the family's pool fence had been built by the girl's father and had not been inspected or certified.

"These circumstances are particularly unfortunate as it appears the fence and the gates were wholly inadequate," he said.

"She appears to have been easily able to gain access through the gates."

The officer in charge of the investigation, Detective Sergeant Kelvin Wicks, said that when he arrived at the family's home on the outskirts of Sydney, he found that the gate did not have a working latch and was not self-closing.

The inquest then heard that, one to two weeks before the drowning, the girl's father had removed one side of the fence entirely, with the intention of moving it closer into the pool.

Both parents said that before this the fence had been compliant with regulations.

"The pool fence was solid for years, but it was just annoying having it [in that position] so we changed it," the girl's mother said.

She said her daughter and other children often rode their bikes and scooters along a circuit that went around the house and past the pool.

Even when the latch on the fence had been functioning, the children, including the five-year-old, had been easily able to wedge it open so they could ride around the path.

She said that the five-year-old had been a strong swimmer and they were not concerned for her safety around the pool.

"[Riding bikes around the pool] is probably not recommended ... but being our kids that's just what she did," she said.

The girl's father said that he had been aware of the need to have the fence properly inspected and certified, but believed that this would be done by the company which installed the pool itself.

He said that when he didn't hear anything from the company he did not follow the matter up.

In his closing remarks to the inquest, Mr Fraser said that neither parent had taken active steps to prevent their children from riding their bikes around the pool, and that the five-year-old had not been closely supervised at the time.

"Whether or not this would have be able to prevent what happened, it certainly created a very grave risk.

"The mere fact that a child can swim on it's own doesn't render the child safe when unsupervised."