ASIO officers have moved to secure the thousands of top secret and classified cabinet files obtained by the ABC, in early morning operations in Canberra and Brisbane.

Key points: ASIO officers delivered safes to ABC offices in Canberra Parliament House and Brisbane

ASIO officers delivered safes to ABC offices in Canberra Parliament House and Brisbane ABC still has access to the documents and is negotiating with Department of Prime Minister & Cabinet

ABC still has access to the documents and is negotiating with Department of Prime Minister & Cabinet Kevin Rudd is launching legal action against the ABC over its coverage

Officers delivered safes to the public broadcaster's Parliament House Bureau and South Bank studios around 1:00am, just hours after the massive Cabinet Files national security breach was revealed.

The ABC still has access to the documents, now kept in the safes, and negotiations are still underway between lawyers for the ABC and the Department of Prime Minister and Cabinet (PM&C).

This morning, former prime minister Kevin Rudd announced he would launch legal action against the ABC over a Cabinet Files story which reported Mr Rudd was warned of "critical risks" in the home insulation scheme introduced by his government.

The report cited in the Cabinet Files does not specify whether any of the "critical risks" associated with the home insulation scheme were safety concerns.

This morning Mr Rudd said any allegation he ignored safety was a lie.

Look inside The Cabinet Files Hundreds of top-secret and highly classified cabinet documents have been obtained by the ABC. Now they're yours to explore. Read more Read more

He said the document reported by the ABC was considered by the Royal Commission into the Home Insulation Scheme ordered by the Abbott government in 2014, which made no findings against him, and that the Royal Commission concluded that while he was serving as prime minister "there was no warning given of the very many problems with the program".

Four insulation installers died during the scheme's rollout.

Decision to publish 'in national interest'

The Department of Prime Minister and Cabinet (PM&C) launched an urgent investigation within an hour of the ABC revealing the trove of documents had been discovered in two locked filing cabinets offloaded to a second-hand furniture depot in Canberra.

But the ABC understands the Australian Federal Police (AFP) are yet to join the inquiry.

The Cabinet Files were locked away in the safe, delivered to the ABC Parliament Bureau by ASIO officers. ( ABC News: Dan Conifer )

ABC news director Gaven Morris said once the story was published, the broadcaster had worked with the Government on the future of the documents.

"This was an agreed process with the Government, we wanted to ensure that as the national broadcaster we were doing all we could to work to ensure the documents were safe," Mr Morris said.

Sorry, this video has expired Cabinet Files: ABC News Director stands by reporting

Mr Morris defended the decision to publish as clearly in the national interest and argued the ABC had been responsible and, "as careful as we could possibly be".

"We haven't gone anywhere near stories or issues that may have a national security implication," he said.

ASIO officers leave the Parliamentary Press Gallery in the early hours of Thursday morning. ( ABC News Dan Conifer )

'They ought to be sacked'

Terry Moran was the secretary of PM&C from 2008 to 2011, and argued the fallout from the incident which has made global headlines should be simple.

"Whoever was responsible for selling a couple of the filing cabinets, which I think were locked, which must have been heavy with all the papers in them, without checking what was in the filing cabinets, apart from anything else they ought to be found and sacked," Mr Moran told the ABC's 7:30 program.

He suggested the departmental investigation may not go far enough.

"I would probably bring the AFP in to do a major investigation," Mr Moran said.

The former senior public servant claimed the breach could be seen as another reason to switch to a paperless system for ministerial documents.

Opposition Leader Bill Shorten has described the incident as "absurd".

"I can't believe it happened, I mean all these spies who are meant to be spying on us — they should just be going shopping in second-hand furniture stores in Canberra," Mr Shorten told ABC Comedy's Tonightly program.

"You shouldn't be able to find information out because someone didn't check a set of filing cabinets, then they sold it at a second-hand government furniture sale.

"Then apparently these filing cabinets were sitting in the shop for some months, and someone decided to get the drill out to break into this one.

"But at least we're on top of it — the Government's on top of national security."

ASIO officers arrive at the ABC building in Brisbane, in the early hours of the morning. ( ABC News )

Wilkie calls for independent probe

Senior public servants, both past and present, have expressed surprise about the almost comical situation of locked, full filing cabinets being allowed into the public domain.

Independent MP and former intelligence analyst Andrew Wilkie called for an independent investigation.

"It's not good enough that the department that might be responsible for the blunder is now investigating itself," he said.

"I was very surprised to read in the media this morning that the AFP have not begun an investigation."

The breach has further highlighted concerns about the scope of new espionage laws being considered by Federal Parliament.

Media organisations argue the new laws would make publishing and reporting on such documents illegal.

"From what I've seen, the documents in those filing cabinets were classified, secret classified documents," Paul Murphy, from the Media, Entertainment and Arts Alliance told the ABC's 7:30 program.

"Therefore under this bill they are defined as inherently harmful information.

"So the communicating of them, any of those documents that were labelled top secret, would come under an aggravated offence with a maximum penalty of 20 years for the journalist and potentially other people in the media organisation for communicating those documents."

The legislation is currently being considered by parliament's intelligence and security committee.