Witnesses described seeing the vehicles "absolutely flying" along the road before the crashes and children emerge from a bus with "blood on their face and clothes" afterwards.
A total of 15 patients were transported to hospital — two by helicopter in a serious condition — after the two buses crashed, about 100m apart, on State Highway 8 near Tekapo yesterday.
Among the passengers were members of a choir that competed at the recent World Choir Games in Auckland.
Mackenzie District Mayor Anne Munro said she felt "really sick" on hearing about the crashes.
But the community had rallied to ensure the passengers were "as comfortable as possible".
The local marae provided lunch and Tekapo’s Dark Sky Project assisted with interpreters.
"Everyone just came together to help these visitors to our community in their time of need.
"I cannot be more proud of how the community responded so quickly."
She believed the majority of passengers had headed back to Christchurch last night by bus, Mrs Munro said.
Christchurch resident Tony McClelland said he saw the two buses "absolutely flying" before the crashes happened.
Mr McClelland said he was travelling at 60kmh to Omarama "scared as hell" and asked police to close the road after skidding on black ice.
Wellington resident Felicity Wong said that she had been travelling from Tekapo to Lake Ohau, when she came across one of the crashed buses.
The 33 passengers on the bus — among them up to 15 children — were still inside, but beginning to make their way out, and emergency services had not yet arrived, she said.
"Some of the children had blood on their face and blood on their clothes," Ms Wong said.
The bus was "very beaten up and some metres away from the road", she said.
"It seemed that the passengers had sore heads from being banged from the bus rolling. They didn’t have gashes and there didn’t seem to be any glass injuries.
"I think there were a few broken bones."
A Hato Hone St John spokesman said the ambulance service was notified of the incident on the Tekapo-Twizel road (SH8) at 8.38am yesterday.
Fifteen patients were transported to hospital, seven from the scene of the crash and eight from Twizel Medical Centre.
Of the seven, two were flown by helicopter to Dunedin and Timaru Hospitals in serious condition, while two in moderate and three in minor condition were taken to Timaru by ambulance.
Of the eight, six were in moderate condition and two had minor injuries.
A police spokesman said there were about 30 people on each bus.
It was understood those on board were international tourists, and the relevant consulate had been advised.
The cause of the crashes was still being determined, he said.
Twizel Community Board member Tracey Gunn said the Hayman Rd intersection with SH8 was "notoriously bad".
"It’s bad without all the black ice and fog."
People who lived in the area were used to the conditions and knew to drive slowly and be careful with braking.
However, tourists coming to the area would have "never driven in these conditions before" and it could be more slippery than one would think, Ms Gunn said.
"With the freezing temperatures, it just turns it into an ice-skating rink."
The weather station at nearby Pukaki Aerodrome indicated the temperature at 8am yesterday was -3°C.
