Australia's former Prime Minister Scott Morrison has been criticized for five ministerial posts he secretly gave himself during his tenure.

The politician, who now sits in Parliament for his conservative Liberal Party, defended his actions at a press conference in Sydney on Wednesday as a precautionary measure during the coronavirus pandemic.

"I felt that in order to act in the national interest, it was necessary to have powers that I could exercise in extreme, unpredictable situations," Morrison said.

He ruled the country from August 2018 to May 2022.

Morrison said it was not a takeover of power.

He also kept his decision secret so as not to undermine his ministers and avoid misunderstandings.

On Tuesday, acting Prime Minister Anthony Albanese said that between March 2020 and May 2021, in addition to his role as Prime Minister, Morrison also had control of the Departments of Health, Finance, Home Affairs, Energy and Resources and the Treasury.

Without officially announcing this, the former Prime Minister was sworn in by Governor General David Hurley and thus gave himself far-reaching powers.

It was only research by the media company News Corp that brought the events to light over the weekend.

Albanese is taking advice from the Attorney General on the case, but has said Morrison did not act illegally.

Morrison said his decision was a "dangerous path" and led a "non-transparent government," he said on Wednesday.

Morrison has also received criticism from within his own ranks.

Four of the five ministers with whom the head of government secretly shared a post say they knew nothing.

Former Home Secretary Karen Andrews, a colleague of Morrison's party, is among other MPs calling for his resignation from Parliament.

The politician said on Wednesday that he wanted to continue in his post.