Emergency services responded in their numbers to two bus crashes on State Highway 8 near Pukaki this morning, in which two people were seriously hurt.
Police said there were two separate single-bus crashes involving buses 100m apart.
Helicopters Otago sent three choppers to the scene, equipped with critical care paramedics to assist any patients needing transport.
Weather conditions were a challenge but "that didn't stop us getting there", managing director and chief pilot Graeme Gale said.
Hato Hone St John said it transported 15 people in total to hospital, including two by air who were in serious condition. Seven were taken straight from the scene to hospital while eight others were transported onwards from Twizel Medical Centre.
Passengers from the buses who did not require medical attention were taken to Twizel.
Two people were seriously injured in the crash, with 15 people in total going to hospital. (Source: 1News)
Do you know more or have footage from the scene? Email: news@tvnz.co.nz
Police said those on board were international tourists, and the relevant Consulate has been advised. The Chinese Embassy confirmed the deputy head of the consulate-general of China in Christchurch was on his way to the scene.
"Our Consular staff have rushed to the hospital to visit the seriously injured," a statement said.
"Our Consulate General has also asked relevant travel agencies to provide proper accommodation and support to other Chinese tourists involved."
The World Choir Games, currently underway in Auckland, said one of the choirs which had competed last week were involved in the crash.
Organisers said in a statement it was "devastated" the choir experienced "such a traumatic event".
"Our thoughts are with the choir, as well as their families at home, and we send our gratitude to those caring for the choirs at this time."
The separate crashes saw 15 people taken to hospital, Jared McCulloch reports. (Source: 1News)
A welfare centre has been set up at the Twizel Events Centre for the 45-50 people who aren't in hospital, said Mackenzie District Council emergency management lead Chris Clarke.
"We're doing things like making sure we've got tea coffee, basic needs and then starting to think about kind of ongoing needs assessment."
Dark Sky Experience in Tekapō made staff available to help with translation, he said.
"The reports are that people are handling a difficult situation well I think we are all very relieved to hear that there were no fatalities as an accident of that scale always brings that possibility."

Tony McClelland, who was driving in the area about 15 minutes ahead of the crash said the driving conditions were "absolutely treacherous".
Fire and Emergency sent multiple trucks to the scene. Police's commercial vehicle safety team were in attendance, and a scene examination was being conducted.
Recovery vehicles are currently en route to the scene to move the buses and bring passenger luggage back to Twizel.
Mackenzie District Mayor Anne Munro said "our thoughts are with everyone involved and their families and friends."
"We are also grateful for the work being done by the emergency services."
Munro said road conditions were poor with ice and freezing fog and she asked motorists to avoid the area and to drive to the conditions to avoid putting undue pressure on the emergency services.
"Weather conditions were foggy at the time," police confirmed, "however, the exact cause of the crashes is still being determined."

The road between SH 8 Tekapo and SH80 Lake Pukaki is back open, NZTA Waka Kotahi said.
What role might weather conditions have played?
Aoraki Area Commander Vicky Walker said it was too early to say if conditions played a part in causing the crash.
"However, it's a good time to mention about winter driving here, whether that's a cause to the accident or not. We are in an alpine environment and the weather condition and road conditions can change quite dramatically quite quickly.
"If you're unsure and feel uncomfortable, turn around and go back from where you came from and either find another route or a safer way of travelling."
Otago Central Area Road Policing Manager Sergeant Steven Watt said he did not want to pre-empt any findings from the inquiries into the bus crashes but he could attest to the challenging conditions for driving.
"It's early infancy of that investigation but I do understand that ice has formed around that area and may have certainly been a contributing factor in that crash."
Watt said icy conditions have been experienced throughout the region.
“We're still investigating a number of crashes throughout the area. What we can say is that ice is evident out there and it's quite clear that that's played a contributing factor in a number of these crashes.”
“Our staff are really busy out there at the moment. With the change of conditions and the icy roads, the nature of tourism that we get coming into area, being unfamiliar with those icy roads, ultimately means that our guys have been busy."
Watt said tending to crashes by those "that perhaps aren't used to the icy conditions" had increased police workload over the last few weeks.
He's pleaded with people to drive to the conditions, respect Mother Nature, and to take their time.
SHARE ME