A major search is underway for two men in the Kaimanawa Forest in the central North Island.
The pair led police on a chase in a stolen car before running into the bush but then made a desperate call to 111 asking for help.
"They have phoned the police communications centre expressing concerns - the fact they're lost, they're cold and one of them was unresponsive," police operations manager Kevin Taylor says.
"We've been able to locate a position through GPS in the phone but unfortunately they were not at that location when we put search teams in the bush."
Five teams of police, helicopters and dogs are searching an area around Tree Trunk Gorge Rd off the Desert Rd.
Searchers have heard them yelling out, found the remnants of a fire and some clothing but nothing else.
"There's no doubt that they'll be hypothermic and there's some real concerns for their livelihoods right now," Mr Taylor says.
Police say neither man has experience in such rugged conditions and were dressed in jeans and cotton shirts when they fled.
"The longer these young men are out there ill-prepared in a bush environment with adverse weather conditions the less likely it is there will be a successful outcome," he says.