A tour bus and a truck have collided in Western Australia injuring 15 people.

The crash happened on Port Gregory Road at Sandy Gully, north of Perth, on Friday morning.

St John Ambulance said 15 patients were assessed by paramedics and all suffered minor injuries.

They were to be taken to hospitals in Northampton and Geraldton for further treatment.

West Australia police said a tour coach was involved but did not give a description of the truck.

Motorists in the area were asked to drive with caution.

– AAP