Police are now working closely with the Canadian and Chinese embassies following the crash.
Robert Durling, chief fire officer of the Athol Volunteer Rural Fire Force, praised the actions of several Australian fishermen who jumped into the river to help the tourists before emergency services arrived.
"When we turned up on scene there were three, at least three, fishermen helping out, trying to rescue as many people out of the river as they could. They did really well," he told RNZ.
"They heard the crash and they were there as fast as they could get there and helped assist as many people as they could, and then when we arrived we helped get the remaining passengers out of the river."
The crash scene was chaotic, with everyone "in a great deal of shock".
There was a "great possibility" that if the fishermen hadn't been there to help rescue the tourists, there could have been more fatalities, he said.
"There was a lot of people in the van and when you're thrown into a river it doesn't take much to lose more people," Mr Durling said.
"It was great that they were there and helped out so quickly, and helped us when we arrived too."
The Australians had "handled themselves really well, really calmly" he said, and it had helped emergency and rescue services assess the situation much more quickly.
The van fell around 3m off the one-lane bridge into the river, and landed on the driver's side, he said.
The tourists left Queenstown about 10.30am and were heading towards Te Anau, but took a diversion to take photos of fish and the river.
Apart from the two teenagers the passengers were all aged between about 45 and 55.
One woman was flown to Dunedin Hospital with suspected chest injuries, accompanied by another member of the party who acted as an interpreter.
The dead man's wife was flown to Southland Hospital with suspected spinal injuries. She was in a moderate condition last night.
The road was reopened after police completed a scene examination last night.
Victim support and the Canadian and Chinese embassies were assisting police.
St John Queenstown station manager Craig Downing said a Chinese man was also flown to Southland Hospital with cuts and a head injury.
Mr Downing said the remaining patients were taken to Southland Hospital to be assessed.
He said the incident happened on a very isolated road on a well-maintained single-lane bridge.
"I think they were extremely lucky given the circumstances of what has actually happened.
"There was extreme potential for more serious injuries to have evolved out of this incident."
Mossburn Volunteer Fire Brigade chief fire officer Lance Hellewell of Lumsden said the van had come to rest on the driver's side and was partially submerged in the river, about 3m below the bridge.
He said the remaining passengers were very lucky to have walked away.
Nokomai Station owner James Hore said it was unusual for a minivan full of Chinese tourists to travel up the road, which was not part of the usual tourist trail.
The one-lane road was not treacherous and just a typical high country gravel road, Mr Hore said.
It was the first major crash on the road in at least 10 years, he said.
- Additional reporting by APNZ and Newstalk ZB
