No charges have been laid by the Australian Federal Police after an investigation into the loss of hundreds of sensitive cabinet documents contained in The Cabinet Files.

The investigation was launched after the ABC obtained the documents, revealing secret cabinet deliberations, from a source who purchased two locked filing cabinets at an ex-government furniture sale.

Some of the cabinet documents were classified as “top secret” or “AUSTEO”, which means they should be seen by Australian eyes only.

Prime Minister Malcolm Turnbull described the breach as a shocking act of negligence and the secretary of his department, Martin Parkinson, has launched a separate investigation.

An AFP spokesman told the ABC the investigation into one of the biggest security breaches in Australian history was thorough, and that no further action would be taken.

The separate review launched by Mr Parkinson has not been released, although the secretary has flagged its findings will have ramifications for the entire public service.

The documents were returned to the Federal Government after a deal was struck with the Prime Minister’s department, which protected the ABC’s source.

Officers from ASIO, the domestic intelligence agency, retrieved papers in Canberra, Melbourne and Brisbane, where they had been temporarily stored in safes at ABC offices.

Some of the revelations from the documents include:

• The Abbott government considered banning anyone under the age of 30 from receiving unemployment benefits
• Then-immigration minister Scott Morrison agreed to enquire about slowing ASIO security checks for asylum seekers, potentially affecting what visas they could receive
• The Howard government gave serious consideration to removing an individual’s unfettered right to remain silent when questioned by police

-ABC