Dramatic dashcam has captured the terrifying moment a hatchback smashed into the side of a motorbike on a busy motorway. 

The grey Yaris and the motorcycle were travelling in the same direction along Sydney's Western Distributor with the hatchback in a lane of traffic banking up to split off onto the Anzac Bridge.

Without warning,the Yaris swerved violently out of the slow moving lane and into the middle lane.

The motorcyclist had no time to react,and was sideswiped by the hatchback.

The footage showed the rider's body and his bike bounced off the concrete partition in the centre of the road and back in front of the Yaris in the middle lane. 

The driver could be seen exiting his vehicle to check on the motorcyclist,who was moving out from underneath his bike. 

The confronting footage has since been shared to the Dam Cam Car Owners Australia Facebook page.

Viewers were horrified by the video,while many others were divided on as to why the Yaris driver swerved the way. 

The car pulled out without warning from a lane of slow moving traffic,hitting the rider

Others just felt sorry for the motorcyclist. 

'No indicator,aggressively changing lanes. The motorbike driver didn’t stand a chance ... hope he is okay,' a sympathetic viewer said.

Another said: 'As unlucky as the bike rider was,it was very fortunate he didn't got over the centre divider into oncoming traffic!'

Sydney