An investigation is under way after a man's body was found in a warehouse in Adelaide's south.

Police were called to a business on O'Sullivan Beach Road in Lonsdale about 2pm yesterday and found a 49-year-old man from Moana unresponsive in a workshop.

The man's cause of death remains unknown.

Forensic investigators remain at the scene as police determine how the man died and if there are any suspicious circumstances.

A report will be prepared for the coroner.

Anyone with information is urged to contact police or Crime Stoppers on 1800 333 000.

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