Australian intelligence officers are believed to have assisted the CIA in undermining Chile's elected government, but the documents surrounding the coup have never been released.
Chilean Australians, all refugees of the Pinochet regime, are angry that Australia has never come clean about the role it played in the coup which tore Chile apart.
On September 11, 1973, the Chilean military attacked the Presidential palace, and seized control of the country from the democratically elected government of Salvadore Allende.
Declassified documents later revealed what many had suspected at the time: Allende's socialist government had been undermined by the Americans.
The CIA link is well known. Less known is the apparent involvement of Australia's two intelligence agencies ASIS and ASIO.
The exact role the Australians played was essentially to backfill four CIA agents who had been expelled by the Allende government.
"The CIA asked ASIS, the Australian intelligence agency at the time, to replace those people with agents from Australia," said Chilean refugee and author Gustavo Martin Montenegro.
Claims Australian agents played an active role in the coup are not new. Newspaper articles began appearing as early as 1974.
Former Prime Minister Gough Whitlam confirmed the story in 1977 when he told Parliament: "I cannot deny it ... Australian intelligence personnel were working as proxies of the CIA in destabilising the government of Chile."
For many Chilean Australians the question is not about confirmation, but transparency.
Files relating to the Australian operations remain closed, still considered matters of national security.
"We wonder why the Australian government continues to keep it so secret," said Chilean refugee Paula Sanchez.
Former victims of the Pinochet regime are also concerned about other possible connections between the Australian government the junta.
There are also concerns that when the junta fell, Australia allowed a number of people connected with the regime to come and live here.
For victims of the junta, the 40th anniversary is a landmark, and a chance, they say, for Australia to reveal its full role and to make amends for what they see as a past mistake.
"I do believe the Australian government should apologise for what happened because it's not just the military coup but it's everything else that happened," said Chilean refugee Mariana Minguez.