A rescuer who plucked a Japanese climber to safety on Friday says the man's climbing partner could still be alive if they had seen a supply pack dropped to them two days ago.
Hideaki Nara, 51, was rescued from Aoraki-Mt Cook at first light on Friday when a break in the weather made it possible for rescuers to reach him.
The body of mountain guide Kiyoshi Ikenouchi, 49, was retrieved later.
The men were trapped at an altitude of 3700 metres for six days, while the mountain in the Southern Alps was lashed by ferocious storms, foiling attempts to rescue the men by helicopter.
The climbers were in the open after their tent collapsed under two metres of new snow. Mr Ikenouchi succumbed to the cold and died some hours before dawn on Friday.
Dave Winterburn, from Alpine Search and Rescue, says the men did not see the 70kg pack containing warm clothes, food and a radio - even though it landed right near their tent.
"That weighs heavily on our minds ... we'd gone to a lot of effort to get the supply pack and when we looked at the photos we thought it's right next door to the tent.
"In all honesty, it's terrible. It's disappointing that they didn't get it, because it could have made the difference."
Department of Conservation area manager for Aoraki-Mt Cook National Park Richard McNamara says the rescue team did a great job in tough conditions.
Police involved in the rescue say there is a huge sense of relief now that the mission is over, but are disappointed they were not able to bring both men off the mountain alive.
Mr Nara suffered frostbite and is recovering in Christchurch Hospital. He is expected to be there for some time.
A spokesperson from the Japanese embassy says he has spoken to Mr Nara, who is very appreciative of the rescue operation.
Mr Ikenouchi became the seventh Japanese national, to die on Aoraki-Mt Cook.