He was Ian Paul Davis (76), of Te Aroha in the Waikato region.
The crash occurred about 4pm on a straight section of State Highway 6, about 3km north of Kingston, as the riders headed to Invercargill for the Burt Munro Challenge, police said.
Pieces of one motorcycle were left strewn across the road and the van came to rest down a bank beside the road.
A second motorcyclist, an Australian, was flown to Dunedin Hospital with serious injuries after the Otago Regional Rescue Helicopter landed on the highway.
The van's five occupants - four female Malaysian tourists and their Christchurch-based driver - were taken to Lakes District Hospital by ambulance with minor to moderate injuries, a St John spokesman said.
Sgt Watt said it appeared the van and at least one motorcycle collided.
''At this stage we're unsure if the second motorbike has collided with that van or was put down prior to hitting the van.''
The cause of the crash was not yet known, as witnesses were still being interviewed and members of the police serious crash and commercial vehicle investigation units were examining the scene, he said.
''Once we have all those pieces of the puzzle together ... hopefully we will be able to begin to paint a picture as to the [cause] of the accident.''
The tourists were being driven north by a Christchurch-based driver.
The crash closed SH6 for more than five hours, leading to substantial traffic delays.
The accident came as motorcycle enthusiasts descended on Southland for the annual Burt Munro Challenge.
Sgt Watt confirmed the riders involved in yesterday's accident had been heading to the event, and urged other road users to take care.
''We'd urge motorcyclists and other traffic to be courteous on the road to each other to ensure everyone has an enjoyable weekend at a popular event,'' Sgt Watt said.
In 2012, Grant Roberts (43), of Timaru, was riding home from the event in a convoy of bikes when he was hit and killed by a tourist driver in the Lindis Pass.
In November last year, Steven Nottingham (59), of Christchurch, and a 70-year-old man were killed in separate crashes while travelling to the event.
Mr Nottingham died on SH6 after his motorcycle, which was towing a trailer, crossed the centre line and collided with a campervan.
Two days later, the 70-year-old man, who was not named, died after crashing his home-built, VW-powered trike into a bank on SH6, about 18km east of Haast.
There will be delays to traffic in both directions on SH6 Kingston, Queenstown from 9am this morning while the Police Serious Crash Unit continue their investigations at the scene of the crash.
