Horrified witnesses have captured the moment a man was knocked unconscious during a road rage brawl on a Melbourne road.

The two men were captured on camera fighting on Toorak Road and Chapel Street in South Yarra at about 10.45am today as witnesses watched on.

The altercation, which occurred between local real estate agent Eddie Letico and a Focus On Furniture delivery truck worker, was caught on camera by multiple witnesses.

Video shows the men brawling on the tram tracks before the delivery truck worker knees the pedestrian in the face and knocks him unconscious.

Mr Letico was then dragged off the road.

"He was crossing and somebody jumped out and attacked him," his wife Maria told 9NEWS.

"He told me he got punched once, but it could've been more times than that."

Mr Letico was taken to hospital with minor facial injuries but those watching the melee claim he was the instigator.