Police are trying to work out how a woman with a distinctive rose tattoo came to be lying on the side of a road north of Auckland with serious head injuries.
The woman was spotted on Waiwhiu Conical Peak Road, in Dome Valley, about 7am today.
Police did not yet know how long she had been lying there, if a car was involved or if she was injured at the scene or elsewhere.
She was flown to Auckland Hospital with serious head injuries and was due to have surgery today, police said.
The woman is European, in 20s or early 30s, and has a tattoo on the outside of her lower left leg. The tattoo is of a cross with a rose and the words mum and dad.
Inspector Mark Fergus said police had been unable to identify her because she couldn't speak.
"We believe the distinctive tattoo on her lower left leg will help us identify her, someone out there will know her."
Witnesses said there was a police cordon at Waiwhiu Road, which comes off State Highway SH1, and several police cars were there.