"She was stabilised on Saturday and her condition has not changed since then. She is still in the Netcare Garden City Hospital," Captain Pinky Tsinyane said.
The girl is the only survivor after her father killed her mother and her three-month-old brother on Saturday in West Park.
Tsinyane said her relatives were at the hospital but it was not known when she would be discharged.
The investigation into the shooting was still ongoing and the motive behind the crime was still to be established, said Tsinyane.