Detective Sergeant Dixie Johnson revealed the mother left a note, asking for the child to be looked after. But she said police also had concerns about the mother's welfare and appealed for her to come forward.
It appears the baby hasn't been born in a hospital," Sergeant Johnson said. "That's why we do want to speak to the mother because we've got concerns about the environment the baby was born in, and we really just need her to come forward to make sure she gets her medical attention and her welfare concerns are looked after.
"If she's not comfortable speaking to police, she's more than welcome speaking to the Department of Communities."
Anyone with any information about the identity of the mother has been asked to call police on 131 444 or Crime Stoppers on 1800 333 000, or report it online.
Police said if the mother did not wish to approach them, she could contact the Department of Communities on 9431 8800, or Crisis Care on 9233 1111 out of hours.