Four trampers plucked off Mt Ngauruhoe last night would probably not have survived until morning, given how cold it was, police say.
A party of eight tourists, aged in their late 20s to early 30s, began a tramp up the mountain about 4pm yesterday.
Four fell and sustained minor injuries and, while the other four went for help, the mountain iced up and the injured group got stuck.
Constable Conrad Smith, of National Park police, said the ice on the mountain was extremely hard and the only option was to rescue the four by helicopter.
He said it was unlikely they would have survived the night, as the wind chill temperature was well below zero.