Forensic Crash Unit officers are investigating a two-vehicle traffic crash at Ironbark overnight.
Preliminary inquiries indicate at 10.55pm a motorbike was travelling west on the Brisbane Valley Highway when it has collided with a sedan travelling in the opposite direction.
The rider of a motorcycle, a Mount Crosby man in his twenties, died at the scene.
The driver and sole occupant of the car has been airlifted to the Royal Brisbane and Women’s Hospital where she remains in a serious condition.
Investigations are continuing.