Police recovered the body of Richard O’Neill-Dean, 70, on Tuesday after the family reported him missing when he did not return from his climb over the previous weekend.
He had set off for the mountains from Lake Tekapo on Saturday and the family understood he would have summited Mt D’Archiac in the Two-Thumb Range on Sunday.
The mountain is the highest peak between the rest of the Aoraki/Mt Cook region and the Kaikoura Range.
Widow Frida O’Neill-Dean described Mr O’Neill-Dean as "strong as an ox".
"He was six foot eight [2.03m] and so active. He had had a hip replacement, but put so much of his effort into rehabilitating and getting ready for climbing. I think he was quite inspiring."
Daughter Esme O’Neill-Dean said he was a "methodical" mountaineer, who had been part of a successful Irish expedition to Mt Everest in the early 1990s and a conscientious worker at his psychotherapy practice.
"Our whole family is in shock," Ms O’Neill-Dean said.
"It was a solo ascent, and he’d wanted to do that mountain for a long time, so he achieved something that he wanted to do.
"We know he summited that mountain on Sunday morning because he rang a climbing friend from the summit.
"But it appears that he broke through the cornice and fell down the south face of the mountain.
"I’m told by the police and the search and rescue team that it was a fall of several hundred metres into rock and would have been unsurvivable."
Mr O’Neill-Dean moved to New Zealand from Ireland in the late 1980s and built up a large community of friends through his psychotherapy practice and within the climbing community.
"He had a huge love of the outdoors and adventures.
"So when he wasn’t climbing, he was someone who loved sailing, loved flying, loved fishing ... so he had a very, very broad range of love of the outdoors which, I suppose, is why immigrating from Ireland, he fell in love with the South Island and all that’s on offer here."
Ms O’Neill-Dean said he was "an extraordinarily careful, diligent, risk-conscious mountaineer".
"There is always risk in the mountains, and he was very aware of that reality, and he was diligent about planning and very, very experienced in mountaineering.
"It was like he would have had that adrenaline rush of having summited, and then he would have fallen so quickly and so conclusively that my hope is that he had no cognitive capacity to realise what was happening."
A spokesman said police received a report of a person overdue from a climbing trip at Mt D’Archiac about 11.30pm on Monday.
"During the search, police search and rescue were assisted by the Aoraki/Mt Cook Alpine Cliff Rescue Team.
"Sadly, the person was located deceased."
A memorial service will be held at 9.30am on Thursday at Hope & Sons in Andersons Bay Rd, Dunedin.
The death has been referred to the coroner.
