Melbourne Crime Investigation Unit detectives are asking for public assistance in the Western Isles to identify the man whose body was found in Melbourne's Yarra River in 1966.
It is understood the police have recently been given information suggesting he may have been a Hebridean exile who emigrated to Australia sometime between the end of the Second World War and September 1966.
His body was recovered from the river in the South Wharf area of Melbourne that month. He was believed to have been in the water between two and four days.
The man was found in grey trousers, black shoes and a double-breasted overcoat.
Investigators recovered a dry cleaning receipt in the name of MacDonald from a pocket in his trousers.
According to Victoria Police, a number of attempts had been made by investigators to establish the man's identity, who was recovered with no apparent injuries or distinctive marks.
Two images have now been compiled by the Criminal Identification Squad, one of the man in 1966 and one of how he may have appeared if he lived to be 80. It is understood this is in case he has close relatives in Scotland who might bear a physical resemblance.
The man may have been one of the more than a million British people who took advantage of an assisted passage scheme established by the Australian Government in 1945 to increase population under its "Populate or Perish" policy. It allowed Britons to travel there for a fare of just £10. They became known as "Ten Pound Poms".
The policy lasted until 1972, with migrants from the Highlands and Islands well represented.
Victoria Police asked anyone with information regarding the man to contact Crime Stoppers via www.crimestoppers.com.au