Oamaru police officers arrived to ''pandemonium'' moments after a truck and a slow-moving school minibus collided on State Highway 1 north of Dunedin yesterday afternoon.
Sergeant Tony Woodbridge was one of four officers returning to North Otago after a day's training when they happened on the scene "one or two minutes" after the crash at the Goodwood Rd intersection, about 3.30pm.
The crash sent a 16-year-old East Otago High School student to Dunedin Hospital with moderate spinal injuries and a 7-year-old boy suffered a moderate head injury.
When Woodbridge arrived "there were a lot of people in panic".
The girl, who was flown to hospital, was "very lucky" she did not suffer worse injuries as the right-hand rear side of the school bus, where she was sitting, was crushed in the impact.
''A school bus headed south was stopped on the side of the road letting children off,'' Woodbridge said at the scene.
''A second school bus was heading south as well and it appears at this stage that that bus has slowed to the correct speed of 20km/h to go past another school bus, but as it was slowing - it had its hazard lights on and was slowing - this other vehicle [the truck] has struck it from behind.''
Ten passengers, from East Otago High School and Palmerston Primary School, as well as the driver, were on the minibus when the crash happened.
The truck driver was uninjured, Woodbridge said.
Otago High principal Lennox Sharp and three other staff were at the scene to check pupils were all right.
''Our students took it in their stride,'' he said.
A witness earlier told the Otago Daily Times there was glass all over the road and some of the windows of the bus, which was still upright, had been smashed.
Students were standing or sitting on the bank near the bus.
Fire brigades and St John ambulances from Palmerston and Waikouaiti, along with a nurse from Waikouaiti, attended the crash.
Police ask any witnesses to contact the Dunedin Central Police Station, on (03) 471 4800.