Albanese said as well as the former prime minister being given joint responsibilities for the health and finance portfolios in March 2020, he assumed responsibility for home affairs and treasury one year later – in early May 2021 – and the industry, science and the resources portfolios the following month.

Albanese said his predecessor had orchestrated an “unprecedented trashing of democracy”.

He said he would receive advice on the matter from the Solicitor-General next Monday, flagging that there was even more to be revealed about Morrison’s behaviour.

“This is a sad indictment of not just Mr Morrison but his cabinet colleagues who sat back and allowed this to happen,” he said.

“I cannot conceive of the mindset that has created this … the way the government has functioned that has led to a point where that occurs and how a cabinet allows that to happen.”

Earlier, the former prime minister defended keeping the multiple portfolios secret, saying they were a safeguard and that he would have made them public had he needed to use the powers involved.

“Sometimes we forget what was happening two years ago and the situation we were dealing with; it was an unconventional time and an unprecedented time,” he told Sydney radio station 2GB on Tuesday.

“Boris Johnson almost died one night. We had ministers go down with Covid.”

Morrison called the actions “a two key approach”.

“We had to take some extraordinary measures to put safeguards in place,” he said.

“Fortunately, none of these in the case of the finance and health portfolio were ever required to be used.

“The powers in those portfolios, they weren’t overseen by cabinet. The minister … in both cases had powers that few, if any, ministers in our federation’s history had.”

Morrison said he didn’t recollect other ministries he took on outside health, finance and resources but documents reveal he was also sworn in to oversee aspects of the social services portfolio.

“No, not to my knowledge no,” Morrison said when asked directly if he was sworn into social services.

Morrison was forced to clarify his position minutes later, saying: “I don’t recall that but I mean, as I said, there was some administrative issues done. I don’t dispute that.

“I’m happy if there are other (portfolios) to be out there.”

An administrative arrangements order for the social services portfolio was signed by Morrison and Governor-General David Hurley on June 28, 2021, on top of him also being privately sworn in as health minister, finance minister and resources minister.

Morrison said all actions were taken to ensure the “buck stopped with the prime minister” as he had no legal powers to directly order a minister to take a certain decision.

“If I wished to be the decision maker, then I had to take the steps that I took,” he said of a call to overrule resources minister Keith Pitt on a controversial NSW gas project, PEP-11.

“People know where the buck stops and the buck stops with the prime minister. I sought to be the decision maker on that issue because of its importance.”

Morrison says his failure to inform then finance minister Mathias Cormann he had been sworn into his portfolio was an oversight, thinking the information had been passed on through offices.

“It was regrettable … but things were moving quickly at the time,” he said.

Pitt issued a statement saying he was unaware Morrison had joint oversight of his portfolio but he stands by the decisions he made.

Prime Minister Anthony Albanese declined to directly express his support for the governor-general when asked to on Tuesday morning, as the Department of Prime Minister and Cabinet inquires into the legality of Morrison’s leadership arrangements.

However, Albanese told the ABC: “The governor-general’s job is to take the advice of the government of the day. I don’t intend to pass judgement.”

A spokesperson for Governor-General David Hurley says he followed processes consistent with the constitution when he appointed Morrison to the additional portfolios.

“It is not uncommon for ministers to be appointed to administer departments other than their portfolio responsibility,” the spokesperson said in a statement.

“These appointments do not require a swearing-in ceremony. The governor-general signs an administrative instrument on the advice of the prime minister.”

Opposition Leader Peter Dutton said he didn’t know Morrison had sworn himself into the cabinet positions.

“Obviously the prime minister had his reasons, his logic for it, but it was not was not a decision that I was a party to or was aware of,” he told ABC Radio on Monday.

Dutton also said he didn’t know whether Morrison had sworn himself in as defence minister, which was his former cabinet position in the coalition government.

The Independent member for Indi Helen Haines has demanded that Morrison explain himself and has welcomed an investigation into the legality of the appointments by the Department of Prime Minister and Cabinet.

“It is a most extraordinary and alarming set of circumstances. There is so much we don’t know. We deserve an explanation around this. Is this setting some kind of strange precedent?” she told the ABC.

Haines says while there was uncertainty around the pandemic and what would happen if the health minister fell ill, there was no reason for the secrecy.

“There is no question that during this period we were in a most difficult time,” she said.

“One could understand how the prime minister may have wished to ensure that there was a safety net, particularly around the role of the health minister.

“But the fact he chose not to tell anyone about this, the fact many members of his cabinet didn’t know about this, but this covered multiple portfolios.

“The prime minister has a responsibility to inform the parliament, the public and to inform his cabinet.”