Mr van Welie's Dunedin-bound furniture delivery truck left the road near Mosgiel, crashed through a fence and careering up to 80m across a property before striking a storage container.
The accident occurred about 11.20pm on Friday, after the truck failed to take a moderate right-hand bend on State Highway 1, about 500m south of Law Rd, acting Senior Sergeant Trevor Thomson, of Dunedin, said.
Emergency services found Mr van Welie dead in his vehicle.
There was frontal damage to the truck.
The cause of the crash was not yet known, and Mr van Welie's death had been referred to the coroner, Snr Sgt Thomson said.
Members of the police serious crash team were involved in the investigation.
Mr van Welie was living in Dunedin but did not have family in the city, he said.
Police were still trying to contact one family member elsewhere in New Zealand.
A crane and tow truck were needed to free the crashed vehicle on Saturday, with the Dunedin-bound lane of SH1 blocked for a short period while the work was carried out.
The second road fatality at the weekend was Penelope Rae Phillips (51), who was killed by a young woman allegedly fleeing a police checkpoint in Blenheim.
Police stopped the 20-year-old Blenheim woman about 9.45pm at a checkpoint, before she sped off and crashed about 400m away at the intersection of Hutcheson and Nelson Sts.
Ms Phillips died at the scene.
Police interviewed the woman yesterday, but it would be some time before a decision was made about laying charges because of the complexity of the investigation, Detective Richard Rolton said.
