Government document leak a "disgraceful act of negligence": Aussie PM

Australia's Prime Minister has called for public servants responsible for classified government documents falling into the hands of journalists to be fired.

The Australian Broadcasting Corporation (ABC) on Wednesday published a series of documents from the Cabinet of Australia, the inner sanctum of government, after they were found in a locked filing cabinet sold at a second-hand government furniture auction.

All the documents have since been returned to the government after lawyers for both parties negotiated their return.

Martin Parkinson, head of the Department of Prime Minister and Cabinet, on Sunday confirmed that his department was responsible for the breach, saying in a statement that it would have implications for the entire public service.

Prime Minister Malcolm Turnbull told the ABC on Sunday that those responsible should lose their jobs.

"This is a disgraceful, almost unbelievable act of negligence," he said.

"The idea that public servants trusted with highly confidential documents would put them in a safe, lock the safe, lose the keys and then sell the safe without checking what was in it beggars belief.

"We want to see those responsible for this negligence identified and dealt with appropriately."

Just hours after the documents were published, officers from the Australian Security Intelligence Organisation (ASIO), Australia's domestic intelligence agency, entered ABC offices in Canberra and Brisbane to secure the documents in a safe.

The breach has reportedly prompted concerns over Australia's security protocols from the U.S., Canada, New Zealand and the United Kingdom; fellow members of the Five Eyes intelligence alliance.

The government has moved to reassure its allies that their secrets are safe.

The Australian Federal Police (AFP) is conducting an investigation into how and when the documents were lost by the department.