Police believe rescuers may have hunkered down for the night with a German tourist who fell into a crevasse high above Fox Glacier in the South Island.
The difficult search was launched about 3.30pm on Thursday and two alpine cliff rescue teams reached the seriously injured woman on the West Coast's Explorer Glacier about 6pm.
Contact between police and rescuers is intermittent because of bad reception.
Search and Rescue coordinator Sergeant Sean Judd said crews are inside the crevasse and trying to keep the woman warm and stabilise her condition on Thursday night.
She has serious injuries to her limbs.
Mr Judd said the woman's boyfriend raised the alarm at a nearby hut.
A police spokesperson said cloud in the area earlier grounded a rescue helicopter which had planned to winch the woman and rescue team out.
The spokesperson believed the helicopter may be grounded until Friday morning.
