A 29-year-old man is in an induced coma after he was assaulted in Subiaco on Friday night.

Police said the man from the Perth suburb of Kingsley was on Hay Street just after midnight when he was punched by another man who then fled the scene.

The victim was taken to Sir Charles Gairdner Hospital.

Detectives were hoping to speak to anyone who was in the area at the time, in particular two people who may have given the victim first aid.

Anyone with information should call Crime Stoppers.