Girl, 2, found dead in bathtub: neighbour

A "gorgeous" little girl has been found dead in the bathtub of her home in Sydney's southwest while her mother lay in hospital, a neighbour says.

Police say they responded to a call from someone concerned for the two-year-old's welfare just after midday on Tuesday and found her body at a home in Miller, near Liverpool.

A neighbour, who did not wish to be named, told AAP she'd been told the toddler had been found drowned in the bathtub.

The home had been unusually quiet for a few days while the toddler's single mother recovered in hospital from a car accident over the weekend, the neighbour said.

"We had someone come us to us asking if we know where the girl is, some friend came up to us in the morning before the police came," she said.

There has never been any trouble at the home - only the sound of the girl's laughter and occasional yells, she said.

Shannon Francisco, whose in-laws live across the road, said: "The little girl was gorgeous ... dark curly hair, she was just gorgeous".

He said he had never seen any trouble in the street.

"That's why it's a big surprise for me," he told reporters at the scene.

Police blocked Merino Street on Tuesday as they talked to neighbours.