Police are still searching for a man who stole a highway patrol car in Sydney's west.

The fully-marked New South Wales police car was stolen during a violent arrest in western Sydney on Sunday.

Police say two highway patrol officers stopped a car on the M7 near the Richmond Road off-ramp around midday.

Officers say there was an altercation and the driver of the car overpowered the officers before breaking free and stealing their patrol car.

The driver, identified as Arthur Partsch, was last seen travelling north in the light blue Holden Commodore sedan.

The car was later found abandoned in a Parramatta street.

Police say they are still searching for Partsch and are forensically examining the car to determine if anything has been stolen or damaged.

Acting commander of the traffic and highway patrol command, Stewart Smith, says officers believe Partsch was on the drug ice.

"Both officers are very experienced," he said. "They were very shaken up from this incident. They certainly have bruising in relation to the altercation."