The Forensic Crash Unit is investigating following a serious traffic crash in Underwood on Saturday afternoon, December 7.

Around 3.36pm, a motorbike was travelling on Compton Road when it has hit the back of a flat-bed truck.

The motorbike rider, a 63-year-old Slacks Creek man, sustained critical injuries and was declared deceased at the scene.

Police are appealing to anyone who may have witnessed the crash, or who may have relevant dashcam vision, to come forward.

The investigation is ongoing.