A man is fighting for life after being found critically injured on a road in Sydney’s west.

Police are seeking information after the 74-year-old man was found unconscious on Orchardleigh St in Yennora about 4.40am on Saturday with life-threatening head injuries.

He was treated at the scene before being rushed to Westmead Hospital.

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Police said the man underwent surgery on Saturday and remained in a critical but stable condition.

After examining the scene and seizing a number of items for forensic examination, detectives believe the man may have been assaulted while on his regular early morning walk.

However, police said the exact circumstances surrounding his injuries remain under investigation.

“As police have been unable to speak with the man, how he came to be injured is unknown,” they said.

“They are speaking with people at the scene who found the injured man and called triple-0.”

The man has been identified as a local resident who is married with three children.

Police are appealing for anyone around Orchardleigh St between 4am and 4.40am on Saturday who has relevant information or dashcam footage to contact crime stoppers.

Police are still unsure how the man sustained his injuries. Credit: 7NEWS