Three-year-old girl found dead in NSW home

A woman is under police guard in hospital after a little girl was found dead in a house in central west NSW.

Police entered the home in Orange about 7.30pm on Thursday after concerns were raised about the residents' welfare.

They found the three-year-old dead in a bedroom and her mother in a semi-conscious state in another room.

The 40-year-old woman was taken to hospital where she remains in a stable condition under police guard, according to NSW Police.

Superintendent Chris Taylor said officers were "taken aback" when they arrived at the scene, as were neighbours who were close to the family.

Early investigations suggest the pair were the only people in the house at the time.

"For the moment we're not looking for anyone else but that may change as the investigation progresses," Supt Taylor told reporters in Orange.

Homicide detectives from Sydney were called in to assist local police, who set up a crime scene and were forensically examining the home.