"While we can reassure the public that we have identified the driver and are speaking with him, we desperately need to identify and speak with the victim here," he said.
"We have checked with all of the hospitals and are making other inquiries. However, at this point we still don't know who this person is.
"There could be any number of reasons as to why that person hasn't come forward or sought medical help, but we'd encourage them to make contact with us as soon as possible, or tell an adult or friend about what has happened."
The driver was a young man, but police would not reveal if charges had been laid against him.
He said the victim was believed to have been crossing Great North Rd between the Mobil service station and Larch St when the Suzuki - driving in the right-hand, east bound lane - struck her.
Police believe the pedestrian hit the car's bonnet and windscreen and was then left lying on the side of the road.
The driver left the scene shortly afterwards and police understand the victim sustained a head wound.
Police have spoken to residents have examined CCTV footage from the Mobil service station.
Information can be reported to Auckland City police on (09) 302 6641, to Detective Sergeant Kevin Blackman on (09) 213 7926 or anonymously via Crimestoppers on 0800 555 111.