Police are treating an incident which left a woman critically injured in South Auckland as unexplained.

She was found lying in a paddock, after the car she was in went down a bank in Waiuku.

Police said her injuries weren't consistent with a car crash - she's currently stable in Auckland Hospital.

Newstalk ZB understands the woman was stabbed, and they're now talking to her family and friends to track down her movements.

They're asking for sightings of her white Subaru Legacy between 6pm Thursday and 6am Friday.

READ MORE: Woman critically injured in paddock after car found run off road