Elderly man 'hit with metal' in road rage attack

Not even a swollen eye could keep 75-year-old Berty Romero from turning up to work at 4am today.

10 hours earlier, the elderly driver had copped a punch to the face in Sydney's latest road rage attack.

It was around 6pm yesterday when Mr Romero crossed paths with a motorcyclist at a roundabout in Bonnyrigg, where both claim the other tried to cut them off.

Both vehicles pulled over on Lalich Avenue and things quickly escalated.

Speaking exclusively to 9NEWS on behalf of his Chilean grandfather, Alex Romero said the rider "smashed the front windscreen, completely shattered the side window, broke the wind visor."

"Grandpa then got out, confronted him about it ... he hit my grandpa in the face with a piece of metal," Alex said.

Mr Romero added he felt targeted because of his age.

Witnesses saw the madness unfolding and pulled out their mobile phones to film the encounter.

The rider can be heard swearing, claiming the Mr Romero's actions forced him on to the footpath.

Sam Orne saw the clash and told 9NEWS he thought the rider was a coward.

"I wouldn't hit an old man. I would have walked away, driven away," he said.

The motorcyclist kept his helmet on during the entire incident, so neither Berty Romero or the onlookers got a good look at his face.

What they did see were the bike's number plates, which were handed to police, who spent the afternoon trying to track him down.

Police are relieved this attack didn't escalate further, but they've reminded anyone in a similar situation to call triple zero immediately, rather than take matters into their own hands.

Anybody with information is urged to contact Crime Stoppers on 1800 333 000.