Lower Hutt man Christoph Huelsmann, killed by a boulder on Mt Taranaki, leaves behind three grandchildren and is remembered as a keen tramper.
Loose scree from the mountain slopes dislodged a large boulder, striking Huelsmann who died at the scene, police said.
"It's pretty heartbreaking," ex-partner Natalie Bould told the New Zealand Herald.
Bould said she had spoken with Huelsmann's family, who had asked for privacy.
"[They're] mourning and they want to remain private."
Huelsmann, 57, had three children and three grandchildren, Bould said. He was a clinical psychologist and practised across Wellington.
Huelsmann specialised in sports psychology and helped write a book, ACT in Sport: Improve Performance through Mindfulness, Acceptance, and Commitment.
New Zealand women's underwater hockey coach Rebecca Brosnan said Huelsmann's psychological training of both men's and women's teams was a key part in them winning the 2018 World Championships.
High jump bronze medallist Imogen Skelton credited Heulsmann with teaching her that "training the mind is just as important as training the body" to succeed in sport.
He had been in New Zealand "for a long time" after moving from Germany, Bould said.
Huelsmann was once national psychology advisor for ACC, according to a social media post from Accuro Health Insurance.
Huelsmann lived in New Zealand for at least 20 years, working in child and adolescent mental health as well as pain and injury rehabilitation.
Bould said he was a keen tramper and had a hiking partner with him when he died.
Police were called to a report a person was critically injured on the mountain about 4pm on Sunday.
Police extended their condolences to Huelsmann's family and friends.
Police Search and Rescue, assisted by the Taranaki Rescue Helicopter Trust team and members of the Taranaki Alpine Cliff Rescue team, worked to recover Huelsmann's body.
Inquiries into the incident were ongoing, but police had completed their inquiries on behalf of the Coroner who would release their findings "in due course", a police spokeswoman said.
Taranaki Alpine Cliff Rescue member Jeremy Beckers flew to the incident by rescue helicopter just after sunset on Sunday.
"Our job was to get the gentleman off who had been killed," Beckers said.
Beckers understood Huelsmann was travelling with someone else when he was struck from above by the boulder.
"He was hit by a large rock ... they come down pretty hard when they fall," Beckers said.
He appeared to have been killed by the boulder on the main route towards the summit, around 2000m up.
Beckers said most alpine people would be aware of the risk of rocks and ice falling on Mt Taranaki.
Department of Conservation Taranaki operations manager Gareth Hopkins said the fatality occurred at the North Ridge of Mt Taranaki Summit Track.
"The death of the tramper yesterday is a reminder of the inherent risks of recreation in the alpine environment. People planning to visit Taranaki Maunga and undertake these activities need to understand the danger the mountain presents.
"Our condolences go to those impacted by yesterday's incident," Hopkins said.
Taranaki Mountain Shuttles won't operate today and Wednesday while the company observes a rāhui "out of respect and cultural protocol" after the death.
The bus company said the rāhui would last two days "or as long as directed".
* This story first appeared in the New Zealand Herald.