The heads of Australia's domestic spy agency and federal police are "excited" about the new security super-ministry, Immigration Minister Peter Dutton says, despite them previously raising concerns.
Mr Dutton, a powerful conservative in the Turnbull Government, will be promoted to the new portfolio, adding ASIO and the Australian Federal Police (AFP) to his existing cabinet responsibilities.
Prime Minister Malcolm Turnbull and Mr Dutton said the restructure was necessary, but would not reveal advice from security agencies showing they supported the change.
A review of the intelligence community by former diplomat Michael L'Estrange did not recommend the Home Affairs Office, despite being asked to consider whether it was "structured appropriately".
Peter Jennings, the executive director at the Australian Strategic Policy Institute, said the Government must provide more detail on the need for change.
But Mr Dutton said the new ministry would never have been announced if there was contrary advice.
"I had my first conversation with Duncan Lewis, the head of ASIO, and with Andrew Colvin, the commissioner of the Australian Federal Police in the last 24 hours or so," he told Sky News.
"I can tell you that both of them are excited about what the Government has announced [and] they are looking forward very much to the new arrangement."
Turnbull says change 'absolutely consistent' with advice
Earlier today, Mr Turnbull said the announcement was "absolutely consistent" with advice he received from his department more than a year ago.
He also dismissed comments by his predecessor, Tony Abbott, who said he was told there was no need to create a home affairs office when he was in government.
Mr Abbott said the announcement was a "massive bureaucratic change", despite indicating support for the proposal just last month.
"I can only assume that the advice has changed since then, and no doubt the Prime Minister will give us more information in due course," Mr Abbot said.
In response, Mr Turnbull said the "logical" announcement had been worked on for more than a year and would improve cooperation between agencies.
"The arguments that have been made against it in the past have been pretty much in line of, 'it's a bit hard, too much trouble'," he said.
AFP and ASIO happy without change
Without any evidence of formal advice from ASIO or the federal police, the comments indicated Mr Lewis and Mr Colvin had set aside some of their previous concerns.
Earlier this year, Mr Lewis said cooperation between ASIO and agencies was already "at an all-time high".
In 2008, he said creating something akin to a US Department of Homeland Security would be "a very large and quote ponderous level of administration".
The Federal Government maintained the new ministry be based on the UK Home Office with separate agencies under one minister, rather than a single integrated department.
In May, Mr Colvin said the current security arrangements were working well and were "quite successful".
John Blaxland from the Australian National University raised concerns about unnecessary change, saying Australia's existing intelligence system was "arguably the envy of the world".
