But Home Affairs minister-designate Peter Dutton on Sunday said ASIO was not likely to join other security agencies until next year, when the government expects Labor's support for laws letting it move into the mega-department.

Mr Dutton revealed the timetable after the Finance Department told senators the government had canvassed the security shake-up as early as February this year, five months before Prime Minister Malcolm Turnbull announced the project.

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But Finance would not reveal if the matter went to cabinet before the Prime Minister's announcement that Home Affairs would house the Immigration department, Australian Border Force and major security agencies.

The Australian Federal Police, the Australian Criminal Intelligence Commission, AUSTRAC, the Office of Transport Safety, and emergency management staff will work under the banner of Home Affairs before the end of 2017, Mr Dutton said.

He told Sky News that under the massive machinery-of-government change due to finish by June, ASIO was likely to move into the new department next year, and that the government expected bipartisan support in February for legislation to move it across.

Mr Dutton said National Security Committee briefings would remain the same, and that the government would adopt a reporting system similar to Britain's.

"There'll be weekly formal briefings from the ASIO head, from all of the other agency heads, and that will inform both the Prime Minister and myself about where the agencies are headed," Mr Dutton said.

While security agencies will remain independent as statutory authorities and continue conducting investigations autonomously, Mr Dutton said they will have a more strategic approach under the Home Affairs portfolio responding to terrorism, espionage and organised crime risks.

The Attorney-General will remain responsible for issuing warrants for ASIO's use of powers, and the spy agency's operations will come into Home Affairs.

Agencies charged with overseeing the intelligence bodies will also move from the Prime Minister's portfolio to the Attorney-General's including the Inspector-General of Intelligence and Security, the Independent National Security Legislation Monitor, and the Commonwealth Ombudsman.

Attorney-General George Brandis said last week Mr Dutton would be sworn-in as Home Affairs minister on December 17.

Secretary-designate Michael Pezzullo previously told senators that, subject to Prime Minister Turnbull's decision, Home Affairs would be operational before February 2018.

While it told senators after a Senate estimates hearing that it was aware of talks to establish Home Affairs in February this year, the Finance Department would not reveal whether the matter went to cabinet, saying those discussions were confidential.

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Labor senator Jenny McAllister told Coalition Finance Minister Mathias Cormann during the October hearings that on many other occasions, the government had said whether or not a matter had been considered by cabinet, as well as the dates of those meetings and whether departmental advice was provided.

"We accept that beyond that the content of the discussion at the cabinet table is not for public consumption and the opposition respects that. But the question of whether or not a matter went to cabinet is conventionally one where the public service does provide information," she said.

Fairfax Media reported last month that under recent estimates subject to change, the new super-size department was expected to absorb 500 staff from the Attorney-General's department, 300 from the Office of Transport Security in Infrastructure, 30 from the department of the Prime Minister and Cabinet, and 18 from Social Services.

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