Police are investigating the death of a baby girl after she was found in a burning house in Sydney’s south-west.

Emergency services found a house on Avon Dam Road, Bargo engulfed in flames on Sunday night.

Fire and Rescue NSW and the Rural Fire Service worked to extinguish the blaze, which destroyed the house.

The body of a five-month-old girl was found inside.

A 79-year-old woman and 57-year-old man were treated for smoke inhalation and lacerations.

A 27-year-old woman was treated for shock and an 18-moth-old boy, who appeared uninjured, was taken to hospital as a precaution.