A man is in a critical condition after being shot in the leg in Melbourne, with police yet to find the gunman.

St Kilda residents found the wounded man on Spenser Street on Friday night.

The 25-year-old victim, who may have been further assaulted after the shooting, was taken to The Alfred hospital in a serious condition with upper and lower body injuries.

A hospital spokeswoman on Saturday afternoon said he is in a critical but stable condition.

The Armed Crime Squad is seeking witnesses or anyone who saw suspicious activity in the area.

The street where the man was found is opposite Luna Park, and next to a large reserve and sports oval.