PM just wants to keep people safe: Dutton

Immigration Minister Peter Dutton has defended the prime minister's decision to form a super home security portfolio which has been criticised as a "captain's pick".

Mr Dutton, who will take over the broad security portfolio that includes ASIO, AFP, Border Force, Immigration and AUSTRAC, said since federation it has been the prime minister's call in terms of government arrangements.

"In the end what was Malcolm Turnbull's intention, what was his desire here, was to do everything within our power to keep the Australian public safe," Mr Dutton told Sky News on Sunday.

He also defended the length of time it would take to form the new home affairs department, saying it was prudent and would allow the agencies to continue their investigations without interruption.

The transition would be managed by a taskforce and be completed by the middle of next year.

"I think it would be a dog's breakfast if you announced it overnight and an effective start from tomorrow," he said.

In the meantime, present arrangements would continue with respective agencies reporting to the justice minister and the attorney-general.

At the same time, the government will be working on the legislation to implement the changes, which Mr Dutton expect's Labor will support.

Even when the changes are made, the attorney-general would still be involved in the warrant process, which Mr Dutton believes is a stronger governance arrangement and a superior model than exists now.

He said the the threat of terrorism is becoming a more serious problem, as seen in the UK.

"People who believe that this threat is going to diminish anytime soon I just don't think understand the depth of concern that we have and the agencies have," he said.

However, he conceded Australia would never have all the resources needed for the surveillance of people who were working on the fringes.

"There will always be prioritisation, it takes a lot of resources to apply surveillance and other techniques that are need to neutralise these threats," he said.