Viggo Nielsen (80), of Woodside, near Outram, was driving a small four-wheel-drive vehicle, police said. It and a truck collided just south of the Taieri River bridge about 1.40pm. Mr Nielsen died at the scene.
He had been travelling north towards Dunedin when his vehicle and a southbound truck, carrying a load of timber, collided, Senior Sergeant Steve Aitken said.
The driver of the truck was not seriously injured, but was taken to Dunedin Hospital for assessment.
SH1 was closed for about five hours while Mosgiel and Dunedin police assisted the serious crash investigation team at the scene.
Southbound traffic was diverted along Henley Rd and northbound traffic along Centre Rd to Allanton.