A CYCLIST has serious head injuries after he collided with a truck on Riverside Drive this morning.

The crash just before 5.30am along Riverside Drive near Plain street when a Hertz truck and the cyclist have collided.

The truck driver has stopped immediately and tried to help the cyclist until paramedics arrived.

The man in his sixties has bleeding on the brain and was sent under priority to Royal Perth Hospital's trauma unit.

The driver has been helping police with their enquires at the scene.