Emergency services have launched a major response to a serious crash between a car and a school bus in rural Canterbury, in which one person is believed to have died.

Six Rangiora High School students were on the bus at the time, Rangiora High School deputy principal Chris Quigley told the Herald.

‘We understand they have minor injuries. Senior staff are on their way out there at the moment,” Quigley said.

The school was contacting the families of the students involved.

The Westpac Rescue Helicopter is on the scene near Sefton in the Waimakariri District.

Emergency services have launched a major response to a serious crash between a car and a school bus in rural Canterbury. Photo / Google

Several patients were being treated for their injuries after the crash happened shortly after 3.30pm, a spokesman for St John Ambulance said.

“I was just trying to get home and came across all this,” said one local man.

”It’s bloody awful. You don’t want to see this. Makes you wonder why they don’t make you wear seatbelts on a bus.”

Police cordons have pushed people away from the crash site.

Emergency services attend a crash involving a car and a school bus near the Canterbury town of Sefton. Photo / Kurt Bayer

Parents of some children involved in the incident have rushed to the scene.

The crash scene is on a rural road, surrounded by farm fields.

Another vehicle involved in the crash appears to be under a blue tarpaulin near the smashed bus.

St John sent three ambulances, two rapid response vehicles, the helicopter and an operations manager to the intersection of Harleston and Broad Rds.

Emergency services attend a crash involving a car and a school bus near the Canterbury town of Sefton. Photo / Kurt Bayer

Initial indications suggest the injured people were in the car, a police spokeswoman said.

“There are no reports of injuries to passengers on the school bus,” she said.

“The road will be closed while emergency services attend,” she said.

Police asked motorists to avoid the area by delaying their travel or using an alternative route.