Homicide detectives are calling for the public's help to identify a man found dead in Melbourne's north-east, four years ago.

The body of the Asian man was found under tree branches on a vacant lot at North Valley Road, Park Orchards in January 2009.

He is believed to have been aged between 25 and 40, and had a distinctive tattoo of an eagle and tiger covering most of his back.

Detective Inspector John Potter says the man was bludgeoned to death.

"Park Orchards doesn't appear to be the place where this type of thing could have happened," he said.

"We're working on the supposition that his death was somewhere else and that he was taken there probably in a car, and dumped on that vacant block."