Three trampers police say were under-prepared have had to be rescued from Mt Ngauruhoe.
Two Pukekohe men and a Dutch woman reached the summit at about 5.30pm on Saturday.
Police say the 18-year-old woman stopped her descent at 2200 metres because of sore ankles. One of the men continued down the mountain to raise the alarm by cellphone.
Senior Constable Barry Shepherd says cloud prevented a helicopter reaching the trampers, so rescuers tramped up Ngauruhoe from South Crater in trying conditions.
He says both the woman and her companion were bitterly cold when rescuers reached them just before midnight.
Senior Constable Shepherd says it took all night to stretcher the woman down the mountain.
He says the trampers didn't have the right gear and set out too late in the day for the tramp they were attempting.
The group would have been all right, police say, had they been wearing appropriate clothing and been prepared for an overnight stay.
