Philip (Phil) James Cox (58) was a passenger in a Toyota car travelling from Roxburgh to Dunedin when it collided with a Toyota Hiace van at 10.15pm.
The van, travelling in the opposite direction, was driven by an overseas man working as a fruit-picker in the Roxburgh area, police said.
The van driver was processed for drink-driving and was in custody awaiting an appearance in the Dunedin District Court today, charged with driving while incapable, Sergeant Ian Kerrisk, of Alexandra, said.
It was likely further charges would be laid.
Mr Cox's friend was taken to Dunedin Hospital with moderate injuries.
Mr Cox had travelled to the Routeburn Valley to go tramping and climbing with his friend but poor conditions and strong winds forced them to return home a few days early, his widow, Jane, said.
Her husband had always been a "very safe" person.
Mr Cox, an oral and maxillo- facial surgeon for more than 30 years, was the only oral surgeon in full-time private practice in Dunedin.
He had taught part-time at the University of Otago Dental School for 26 years, where he was known for teaching his students to be compassionate first and foremost.
A keen sportsman, he competed in 13 Coast to Coast and 12 Southern Traverse races and was involved with children's athletics.
He had two children.
The highway was closed overnight, with a detour in place, and Sgt Kerrisk said while police were dealing with the crash, two Invercargill men took two warning lights from the accident scene.
"The theft put emergency services and the public at risk," he said.
The men were charged with theft and will appear in the Invercargill District Court on Friday.
