The daylight attack happened near the Crown Street entrance to West Wollongong Public School just before 9am.

According to police, a 52-year-old man was sitting on the side of the street when he was approached by two men and assaulted.

The man's wallet was stolen and the two offenders fled the scene.

Police believe the men were known to each other.

Emma Jacobs works in the Caltex service station across the road and looked on in horror as the assault unfolded.

"We heard somebody yelling and we could hear him yelling 'help'," the 20-year-old told the Mercury.

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Ms Jacobs ran to the window to see what was happening and said she saw a man "on the ground with two other guys on top of him".

"There were two young men, they looked about in their 20s, and they were just bashing him [the other man] and you could see him [one of the offenders] grab something from his pocket," she said.

"They didn't look like they were physically punching him, they were trying to hold him down on the ground."

The assault was captured on one of the servo's CCTV cameras. The vision, seen by the Mercury, shows two men walking east along the Crown Street footpath from Mount Keira Road.

They stop outside the school gate, where it appears the 52-year-old was sitting.

A number of other pedestrians walk past, before all three men begin to walk along the footpath.

The assault takes place a short time later, with the vision capturing the moment the man was pinned to the ground and stripped of his wallet.

The footage then shows both the attackers - one wearing a high-vis hoodie and black pants, the other shirtless - running into the nearby school grounds.

Drivers on busy Crown Street watched on from their cars. There was no one else on the footpath at the time of the assault.

Ms Jacobs said the injured man try to chase down his attackers, but was unsuccessful. He returned the to scene of the assault and then made his way to the Caltex.

"All his stuff was left on the side of the street. He had what looked like a shopping bag and it was kind of scattered on the side of the path," Ms Jacobs said.

"He came in afterwards and he had scratches on his head and his hands and ... he kept rubbing down his arm. He said that he was feeling sore."

Another servo employee said the man had "blood everywhere" when he came in and bought a packet of Tally Ho papers.

Ms Jacobs said the assault was "a bit of a shock" and concerning, given the proximity to the school.

"We were a bit surprised, I kind of didn't know what to do," she said.

"I wanted to help but I couldn't help or do anything at that point of time."

Other people came to the injured man's aid.

Paramedics were called a short time later.

A NSW Ambulance spokeswoman said one ambulance responded following reports man in his 50s had been assaulted.

The spokeswoman said the man was not transported to hospital.

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