Motorists approaching the Sydney Harbour Bridge are facing delays after two separate car accidents blocked lanes.

A four-wheel-drive slammed into a toll booth at the northern entrance to the Harbour Bridge on the Cahill Expressway, blocking two lanes, just before 6.20am.

Two people in the car were freed by emergency personnel, and were taken to Royal Prince Alfred Hospital for further medical checks.

Police said their injuries were not considered to be life threatening.