"That caused people to get thrown around and be injured."
Bark was at Lakes Hospital where some of the injured had been taken when he spoke to the Herald and said staff at the company were "very concerned" about the welfare of the crash victims.
"It would be an upsetting event to go through."
He was yet to speak to the driver, so couldn't confirm why the driver had to swerve off the road, but said an internal investigation was underway.
A St John ambulance spokeswoman said a child was seriously hurt and three adults moderately injured in the incident.
She told the Herald two helicopters and three ambulances were sent to the scene.
The injured child was likely to be flown to Dunedin Hospital and the adults would be taken to Lakes Hospital.
Police said up to five people suffered minor injuries and the child was taken to hospital by chopper as a precaution.
The area had snowfall today and a police spokeswoman said the roads were slippery.
Speaking to media at the scene, Sergeant Keith Newell of Queenstown police praised the bus driver's actions.
"The driver's done an excellent job and he's put it in the ditch. The alternative wasn't worth thinking about," he said.
"It could have been a lot worse."
Police had spoken to the driver, who was unhurt but shaken, Newell said.
The cause of the crash was still unclear but the bus would be inspected for mechanical faults, he said.
The vehicle would remain at the scene overnight because poor weather conditions would make it too difficult to get out. It would be recovered in the morning.
The Remarkables ski area manager Ross Lawrence said the crash happened about 8.5km up the road from State Highway 6.
"[The bus] left the road on the left-hand side and went into the watercourse."
He wasn't sure what had caused the vehicle to veer off the road, but said all vehicles using the road today had to use chains because of the recent snowfall.
Lawrence told the Herald the bus involved was a charter vehicle and the people on board had been skiing today.
He was unable to confirm whether the passengers were tourists or locals.
Ski patrol and medics from the ski field rushed to the scene after being alerted to the crash and attended to the injured while waiting for paramedics to arrive.