But the plan – arguably the biggest shake-up in the structure of Australia's national security apparatus in decades – is likely to be fiercely debated in cabinet. Attorney-General George Brandis, Foreign Minister Julie Bishop, Justice Minister Michael Keenan and Defence Minister Marise Payne are all understood to oppose the idea. Defence Industry Minister Christopher Pyne is understood to lean against the idea. The Prime Minister backed by rows of gas-masked, camo-clad, machine-gun-toting special forces. Credit:Ben Rushton A source familiar with the expected changes said Mr Turnbull had consulted at length with cabinet colleagues over the machinery of government changes and stressed that no one would lose their ministerial portfolio. However Senator Brandis, currently responsible for ASIO, and Mr Keenan, responsible for the AFP, would be the big losers out of the change. Sources in the security community have broadly questioned why the changes are needed - arguing information-sharing is already strong - and some influential figures in government have argued that Australia has a better track record than Britain in preventing terrorist attacks.

In London last week, Mr Turnbull met with British Home Affairs Minister Amber Rudd and her predecessor in the role, current Prime Minister Theresa May, to discuss how the British Home Office worked and hinted changes were imminent. Prime Minister Malcolm Turnbull with Immigration Minister Peter Dutton. Credit:Alex Ellinghausen On Monday, he said "these administrative matters are often under discussion and considered". "We have got outstanding arrangements in Australia. We are always open to improving them. Again, there is no place for set and forget." Illustration: Matt Golding

However, Mr Keenan said on Monday morning that "I don't believe any country is as well-equipped to deal with the terrorism challenges as Australia". The Immigration Department would lose responsibility for border protection and instead concentrate on issues such as integration and citizenship. The Australian Criminal Intelligence Commission, which co-ordinates national law enforcement and financial intelligence agency AUSTRAC - both part of Mr Keenan's portfolio - would also come into the new super-portfolio. Mr Dutton is known to be in favour of the idea, while Treasurer Scott Morrison and Finance Minister Mathias Cormann are also understood to back the move, which was considered by former prime minister Tony Abbott. Mr Turnbull is expected to announce the change as he unveils a review of national security arrangements by former Department of Foreign Affairs head Michael L'Estrange.

However that L'Estrange review is understood not to specifically recommend such a super-portfolio. Security and intelligence agencies are believed to have some concerns about any change. But a well-placed source in the intelligence community said a Home Affairs office - as opposed to a US-style Department of Homeland Security - was the preferred options for police and intelligence agencies. That was because a Home Affairs department would potentially be broader, including agencies such as the Computer Emergency Response Team, the Australian Cyber Security Centre, AUSTRAC, the ACIC and the new Critical Infrastructure Centre, rather than just police and intelligence agencies. John Blaxland, a security and intelligence expert from the Australian National University who has co-written the official history of ASIO, said power should not be concentrated so heavily with one minister and department. "I'm not making any comment on current people but there are compelling reasons why the separation of powers on an enduring basis is a good thing. Concentrating such power can generate concerns about how that power might be used perhaps inappropriately," he said.

He said current arrangements were the product of years of refinement and improvement. Acting shadow attorney-general Katy Gallagher said any changes should be based on recommendations from security experts. She suggested Mr Turnbull was planning the change to keep the right wing of his party - represented by Mr Dutton - happy. Loading "Australians would be very concerned if a new national security super department is being created just to keep Peter Dutton happy, especially when it's so vehemently opposed by so many of his colleagues," she said. Follow us on Facebook