The driver of a car, who was being followed by police, has died after colliding with a school bus in Sydney's west and injuring several students.

The crash occurred about 8.00am at the intersection of Londonderry Road and The Driftway, after the car went through an intersection without slowing and crashed into the bus.

Five students were treated at the scene by ambulance paramedics, and two of them were taken to Hawkesbury Hospital with minor head injuries.

The man driving the sedan died at the scene.

The driver of the bus was not injured but was taken to hospital for mandatory testing.

Acting Commander of the North West Metropolitan Area Jeff Philippe said the car was seen violating a traffic regulation which led the police to follow the car.

When asked whether it was wise for the police to pursue a car in peak hour, Acting Commander Philippe said the intersection is in a low-density traffic area and whether it was a pursuit was a question for the critical investigation team.

The deceased driver of the sedan is still being identified and police are preparing a report for the coroner.

Acting Commander Philippe said the bus driver demonstrated bravery and composure in helping the children off the bus.