Police are seeking out relatives of a man who disappeared in the South-West National Park 50 years ago.
The call-out is part of a review into the disappearance of John Boyle who went missing from part of a group exploring Mount Anne in October 1969.
Mr Boyle, then aged 26, had moved from Sydney to Hobart several months before he went missing.
Police said during the hike, he was separated from the group and disappeared without a trace despite an extensive search.
Officers want to speak with relatives of Mr Boyle who was the son of Fairfield man Edward Boyle and brother of Ken Boyle.
"Given the passage of time since Mr Boyle's disappearance, a report is being prepared for the coroner and, as such, we're reaching out across Australia with the aim of finding a sibling, a cousin or any other relative," Sergeant John Delpero said.
Relatives of Mr Boyle are asked to contact Tasmania Police on (03) 6173 2426 during business hours.