A tramper with serious injuries was found by rescuers sleeping precariously close to the edge of a cliff, more than 2000 metres up Mt Ruapehu.
The woman was attempting to walk to the summit of the mountain yesterday afternoon when she became lost and fell, badly injuring her head, police said.
A friend was able to relay the information to police and rescue teams, but her exact location was unknown.
Greenlea Rescue Helicopter, which was called in to help with the search, said the woman had only been able to provide some "cryptic clues relating to a river, a waterfall, and possibly a hut".
Search teams and two rescue helicopters scoured likely areas where the woman could be, in fading light and poor weather conditions.
Just as weather was threatening to hamper the search, the missing woman was able to get some cellphone coverage and send her GPS location to police, Constable Aaron Owen said.
Searchers then tramped for five hours to reach the woman at about 1.30am, in the Whangaehu river gorge on the opposite side of the mountain from where she had intended to be.
[She was] huddled in her sleeping bag perched right on the edge of a cliff at an elevation of just below 7000 feet [2100m]," Greenlea Rescue Helicopter said.
She was cold, tired and had obvious head and facial injuries.
Rescuers took the woman to a nearby alpine hut for the night and the rescue helicopter was able to fly her out at first light.
Pieceing together what had happened, the rescue helicopter crew said it appeared she had fallen late yesterday afternoon, "losing consciousness in the process".
"She was unaware what had happened to her and where all the blood on her head and face had come from. She may also have fallen a second time in her dazed state."
She was taken to hospital with multiple serious injuries.
"Given the environment in which she was found it is extremely fortunate that she did not come to more harm, despite sustaining considerable injuries," the crew said.
Police said people venturing into the back country should ensure they leave their travel plans with a friend, and carry the correct equipment including a personal locater beacon.