A truck driver suffered serious head injuries after police say he came to the rescue of an elderly man being threatened by boys armed with bricks.

The alleged assault took place on December 29 about 11.30am on Pinedale Street in East Victoria Park.

Police said the truck driver stopped to help an elderly man being threatened by three boys carrying bricks.

The man took one of the bricks from the boys and ordered to them to leave, police said.

After the driver re-entered his truck and started to drive off one of the boys allegedly threw a brick into the open cab window, hitting the victim in the head and damaging the front windscreen.

Police said the boys ran away long Pinedale Street before turning right onto Creaton Street.

The driver was taken to Royal Perth Hospital for treatment of serious head injuries he sustained.

Police have released CCTV footage, in the player window above, hoping someone might be able to identify the boys.

Anyone with information is asked to contact Crime Stoppers on 1800 333 000.