A mother and daughter who became lost in the Central North Island bush had to huddle together for warmth and ration their supplies after the terrain became impenetrable, police say.
Carolyn and Rachel Lloyd failed to return from what was supposed to be a day hike on the Kapakapanui Track in the Tararua Forest Park on Tuesday, prompting a huge search and rescue operation.
Sergeant Anthony Harmer told reporters that the pair were spotted by an experienced local helicopter pilot earlier today.
They have been airlifted to Kenepuru Hospital for precautionary checks after their miracle survival.
"They've ended up becoming a bit disorientated and heading off the main track down into an unexpected waterway, where they've become stranded by their circumstances and ended up having to ration their resources [and] stay together for warmth," he said.
"They've ended up in a very steep and rugged area of terrain, so steep at times that they felt that they weren't able to return ... the way that they had come, so ended up going further down and ended up in a water catchment area where they were unable to progress out."
The water catchment was a stream of sorts, he said.
Both were thought to be in good health following their ordeal but were being checked over by medical staff as a precaution.
"They're obviously a little bit worse for wear - dehydrated and exhausted."
A search and rescue operation began yesterday after their vehicle was discovered at the entrance to the track.
Sergeant Harmer said the mother and daughter were experienced day hikers, having completed the Appalachian Trail and numerous other hikes in their native United States.
He praised them for how they had handled their situation.
"They've been caught out unawares in their circumstances to no fault of their own. It's a New Zealand environment as opposed to other environments that they've been to.
"They've done all the right things once they have found that they're disorientated - they've stayed together, they've conserved their heat, they've conserved their resources so they gave themselves the best chance possible."
The brother and uncle of the two women has expressed his relief after their discovery.
Posting on Facebook, Bob Schumacher said "our prayers have been answered".
"My sister and niece have been found alive. They are being helicoptered out. My sister is okay, my niece is a little weak, but both should be just fine."
Police and search and rescue crews began scouring the Tararua Forest Park near Waikanae for Carolyn, 45, and Rachel Lloyd, 22, after their rental car was found at the entrance of the track yesterday.
Four teams of eight people were sent out to search for the missing pair, with a mix of police and search and rescue volunteers.
Two dog teams, helicopters and all-terrain vehicles were made available for the search.
The back window of the their rental car had been smashed, with glass visible inside the car.
Police were unsure if the glass was broken before or after the two went missing.
Miss Lloyd had travelled to New Zealand to study at Massey University for a semester.
Her mother is visiting from their home in the United States.
Massey University spokesman James Gardiner said Rachel was at the university on a one-semester exchange and had arrived from the US in February.
"We will offer Rachel's father transport to New Zealand, and are offering the family our support," Mr Gardiner said.
"We don't know what the situation is yet, but it is very worrying."
Tykori K. Saunders posted on Facebook that one of his "best friends" was missing.
"My heart goes out to you and your mother Rachel Lloyd. I pray that you and you're found safe and sound soon! I love and miss you Rachel." [sic]
Mackenzie Hines asked her followers to "say a prayer that this sweet sorority sister of mine, Rachel, and her mom are found and are okay".
Tessa Bradlie Souffrant posted "My grandbig and her mom are missing while she is abroad in New Zealand".
"Please pray that they find them both alive and well!"
Tararua Tramping Club president Peter Barber said it would be difficult to get lost on the track.
"You go up one side and come down the other.
"But it is quite steep. The weather's been pretty good. It can be harder when it's not so good."
Mr Barber said it was important hikers always told someone where they were going, and carried good gear, extra food, a personal locator beacon and GPS.
Sergeant Harmer urged people to check the website www.adventuresmart.org.nz before heading into the New Zealand wilderness.