Police, fire service and ambulance crews were called to a two-vehicle collision on St Marys Road, near the junction with Hillview Road.
It appeared that a car and a motorbike were travelling in opposite directions when the crash happened at about 9.15pm.
A BPS spokesman explained: Early information indicates that the male rider sustained head injuries.
He has been rushed to King Edward VII Memorial Hospital via ambulance.
Traffic was diverted while officers worked at the scene.
Witnesses were asked to call police on 295-0011.