Four people have been taken to hospital after a school bus travelling to a special developmental school rolled on a country road in Minyip in Victoria’s north-west.

Emergency crews worked for more than an hour to free the bus driver after the crash involving a B-double carrying hay bales on Thursday morning in the hamlet in the Wimmera region.

A bus driver was trapped for more than an hour after a school bus rolled in country Victoria.

Three children and another adult were passengers on the bus at the time.

The bus driver was flown to a Melbourne hospital with serious injuries, while two children and the truck driver were taken to Horsham hospital.

The accident happened about 8.30am near the intersection of Stawell-Warracknabeal Road and Minyip-Dimboola Road in Minyip, about 51 kilometres north-east of Horsham.

The 22-seat school bus, travelling to Warracknabeal Special Developmental School, rolled onto its roof while the B-double hay trailer landed on its side.

Four people were taken to hospital.

The school caters for students with disabilities aged 5-18 years from Warracknabeal and surrounding areas, according to its website.

The female bus driver was trapped for more than an hour before she was freed by 9.45am, the Country Fire Authority said. Police said she sustained serious injuries in the crash.

The bus was carrying three students, a staff member from the school and a driver at the time of the collision, a Department of Education spokesperson said on Thursday afternoon.

“Two of the students were transported to hospital for observation, and the third student is otherwise safe and well,” the spokesperson said.

“Additional wellbeing support is available to students and staff at Warracknabeal SDS, Warracknabeal Secondary College and Warracknabeal Primary School – and all families have been informed of the accident.

“Our thoughts also go to the drivers of the bus and truck.”

A specialist Ambulance Victoria helicopter crew and six advanced life support paramedic crews arrived at the crash site about 8.50am.

“Following emergency on-site care by our crews, two people have been transported by road ambulance to Horsham hospital and one person has been airlifted to The Alfred,” an Ambulance Victoria spokeswoman said.