Officer dragged 25 metres on Sydney road

A police officer has been dragged 25 metres along a Sydney road after he attempted to arrest a driver.

The senior constable pulled over the driver at Harris Park in western Sydney on Monday morning after he allegedly failed to stop at a stop sign.

When the officer asked him to hand over his driver's licence and keys, he allegedly refused.

Police say the officer then opened the door and tried to arrest the man but he drove off about 20km/h.

The officer was allegedly dragged for about 25 metres before falling to the ground.

He suffered grazes to his right arm and left palm.

Police are looking for an obese man of Caucasian appearance, aged 40 to 50 with a grey beard.

He was wearing a fluorescent-yellow work shirt.

His car is described as being a late-90s model, blue-and-silver Toyota Prado.