The outgoing Human Rights Commission president, Gillian Triggs, has said the creation of a new “super ministry” of home affairs was part of a hastening trend towards centralised and unchallengeable government power.

In a wide-ranging valedictory interview on ABC radio in Melbourne, Triggs also said a concerted campaign to amend section 18C of the Racial Discrimination Act had faded in the face of resolute public support for the section and that she felt she became a “lightning rod” for controversial rights issues.

Triggs, who finishes her five-year term as Human Rights Commission president on Wednesday and will take up a post at the University of Melbourne next month, said the consolidation of power within the executive represented a “very serious incursion into the separation of powers, the power of the judiciary to make independent judgments”.

Home affairs – to be immigration minister Peter Dutton’s portfolio from next year – will combine the Australian federal police, the Australian Security Intelligence Organisation and border force in a new ministry broadly modelled on the UK’s home office.

“Over the last few years, and particular during my time as president, we’ve seen this initially quite slow movement, piece of legislation by piece of legislations, that centralises administrative and ministerial decision-making,” Triggs said.

“But the last few weeks are seeing almost a galloping move towards a centralisation of government but most particularly of expanded ministerial discretion without proper judicial supervision and control.”

Triggs said she did not oppose government reorganisation or consolidation on principle but that the case had not been made by the government that Australia was on a “war footing” against the forces of international terrorism that required extraordinary powers.

“I think the public would accept certain restrictions on freedom in order to ensure Australia has a very safe set of laws to ensure national security,” she said. “My concern is primarily is that there is no public information or discussion about this and no processes in place to ensure protection of those rights.”

She said many ministerial discretions, particularly around counter-terrorism and immigration decisions, were not subject to judicial review, a “very serious incursions into the separation of powers, the power of the judiciary to make independent judgments”.

Triggs said the attacks levelled at her during her term as commission president had been “exceptional, possibly even unprecedented” but that those were the public front of a more fundamental ideological assault on the commission itself. Triggs said the ad hominem attacks were wasteful and failed to progress the issues.

“I’ve simply been chosen as a lightening rod for issues, obviously asylum seekers, where we took the inquiry, but also 18C,” she said. “I think that there’s been a strategic advantage in attacking the individual rather than the point at issue.

“And I think that’s particularly unfortunate because I would much rather prefer a full-on debate about the issue where we could get on the table what is working and what’s not about 18C and D, why we are not meeting our legal obligations in relation to asylum seekers and refugees. I would much rather a healthy debate about that … rather than turn it into an attack against me, a highly personal one. It just doesn’t achieve anything.

“The issues remain unresolved and nothing’s been achieved.”

Triggs’s term as AHRC president has been marked by profound and consistent disagreement with members of the government, in particular over the commission’s inquiry into children in immigration detention and her defence of section 18C of the Racial Discrimination Act.

She said the campaign to change 18C appeared to have been exhausted.

“It was clearly being run by a small number of people absolutely determined that there would be change,” she said. “What I think they failed to understand and, indeed, both the Abbott and Turnbull governments failed to understand, is the very strong support within not only the multicultural or ethnic communities but within the Australian community generally.

“I think there’s a distrust of government and a concern that amendments as were being suggested were actually not going to ensure that Australia maintains some level of social harmony on questions of racial abuse.”

Triggs reiterated her position that strictures of 18C was sufficiently counterbalanced by the protections of 18D and said she hoped to see an Australian bill of rights or human rights charter in her lifetime. Victoria and the ACT already have human rights charters and the Queensland government is debating the issue.