A manhunt is underway for a driver who ran down a police officer on EastLink and then fled, prompting the senior constable to open fire.

The man was detected driving a car with stolen number plates about 1.20pm near the exit of the city-bound Melba tunnel in Donvale, and was directed to pull over by police conducting a random road operation.

Instead, he accelerated at an experienced senior constable from the Highway Patrol, aged in his 30s, striking him with the front of the car.

The force caused the policeman to bounce into the windscreen of the vehicle before being thrown onto the roadway, according to police. At some stage during the incident the officer had fired a single shot.