A woman has died and another is in a critical condition after a Queensland school bus collided with a car on the Warrego Highway, north-west of Toowoomba.

The 30-year-old Chinchilla woman was a passenger in the car and died at the scene.

The driver of the car, a 37-year-old Western Downs woman, was taken to hospital in a critical condition, police said.

The two adults were trapped in the car and a Queensland Fire and Emergency Services spokeswoman said crews cut the door and roof off the car to reach them.

The Warrego Highway remained closed for several hours on Friday evening while the Forensic Crash Unit carried out investigations.

Police said the car and school bus collided about 10 kilometres from Wallumbilla at about 3:00pm.

The Education Department confirmed in a statement that the bus was carrying students from Wallumbilla State School.

The Queensland Police Service statement said the 17 passengers of the bus, including the 58-year-old driver, did not suffer life-threatening injuries, but one child did suffer multiple leg fractures.

"Guidance officer support is being offered to all affected students that may require assistance," the Education Department statement said.