A man who fell from a ridge on the country's tallest mountain is dead, police have confirmed.
Police said four "experienced climbers" from the Canterbury region were understood to have set out from Plateau Hut early this morning to climb Aoraki-Mount Cook's east ridge.
They raised the alarm about 7.30am after one of their team fell as they traversed the ridge.
A search and rescue operation was launched involving police, and the Aoraki Alpine Rescue Team.
That was changed to a body recovery operation this afternoon.
Police said the Canterbury man's death had been referred to the coroner and none of his details would be released until formal identification had taken place and his next of kin informed.
The three uninjured members of the climbing party had returned to Plateau Hut to be picked up by a Heli Line helicopter.
The search and rescue team was being brought back to the Mt Cook Emergency Centre where planning for the recovery operation was underway.
The weather in Mt Cook village was improving with scattered cloud clearing. The recovery site was understood to be above cloud level.
Police said the recovery wold take place as soon as it was practical.
Canterbury Rural Area Commander (Mid South) Inspector Dave Gaskin said it was a tragic start to the climbing season.
"Our thoughts go out to the friends and family of the climber and the other members of his climbing party.
"The east ridge of Aoraki Mt Cook is an extreme climbing area. The group of climbers were very experienced and were well prepared and had planned their trip in advance. Unfortunately very rare incidents such as this occur from time to time."