The ambulance has been taken off the road.
People are being asked to avoid the area.
The road is expected to remain closed for some time.
The crash was reported at 1:30pm.
The evidence was kept from the coroner for almost a week into the inquest.
The 11-year-old died after a bus lost control and crashed on Mt Ruapehu.
"These aren't just marks, these are all real people."
The police have been notified of the dangerous driving.
St Johns says early indications are there are multiple patients.