A motorcyclist has been tackled to the ground while allegedly trying to do a runner after crashing into a motorbike cop in Brisbane's north.

The Road Policing Command senior constable was on speed camera duties near a school at Geebung, near the intersection of Newman and Robinson Roads on Tuesday when he saw a motorbike that was allegedly involved in traffic-related offences in the area recently.

Police said the officer parked his motorcycle in front of the bike just before 4pm and activated his lights.

The other bike then allegedly reversed and drove into the officer’s bike before they both knocked to the ground.