A man has been found lying on a road seriously injured following an alleged road rage incident.

Police found a 55-year-old man with significant head injuries on South Terrace, Punchbowl in Sydney’s southwest just before 10pm on Friday.

He was treated by paramedics before being taken to hospital in a stable condition.

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It’s believed the man had been assaulted during an alleged road rage incident.

One witness told 7NEWS he saw two men jump out of a car behind the victim’s vehicle.

“I was just coming up the street and I saw them bash him (the victim) and drove off,” he said.

“It was like two-on-one.”

Police are investigating the incident.

Anyone with information about the incident or any dashcam/ CCTV footage is urged to contact Crime Stoppers.