Melbourne hotel worker punched in face

A Melbourne hotel worker has been punched in the face in an unprovoked attack as he left the pub.

The 37-year-old man was going out of the rear door of the Swanston street hotel when he was attacked just after midday on January 4.

"As he opened the door he was confronted by an unknown man who yelled at him, then punched him in the face," according to a Victoria Police statement.

Police have released security camera images of the attacker.