WA shop owner hit by flying concrete

A Perth shop owner has serious facial injuries after being knocked unconscious by a chunk of concrete allegedly thrown by a boy.

The man had asked a group of youngsters to move from a table outside Hamburger Hill in Scarborough on Sunday so customers could sit there, when they became aggressive.

He retreated to his shop and called security, who attempted to move the group on.

Police say the shop owner was knocked unconscious by a piece of concrete allegedly thrown by one of the boys before they fled.

The victim was taken to Royal Perth Hospital and is expected to undergo surgery on Monday.

Anyone with information about the incident is asked to contact police.