Scott Morrison has given a curt response to criticism that he “trashed” the democratic process by having himself secretly sworn into other cabinet ministers’ portfolios while prime minister.

Mr Morrison’s successor as Prime Minister, Anthony Albanese, on Monday described the clandestine arrangements as “trashing” democratic process and said his predecessor had run a “shambles” government that was not real.

Sky News anchor Kieran Gilbert revealed he had texted Mr Morrison extending him a right of reply to those comments – and received a sharp reply.

“Since leaving the job I haven’t engaged in any day to day politics,’’ Gilbert reported Mr Morrison texting.

The claims were revealed at the weekend, in an extract from a book by News Corp journalists. It says Mr Morrison secretly took on the health and finance portfolios when the COVID pandemic reached Australia in March 2020.

It has also been reported that former resources minister, Nationals MP Keith Pitt, also jointly shared responsibilities with Mr Morrison. He learned of the arrangement only during a fight over a politically contentious offshore gas project, which Mr Morrison opposed. 

Mr Pitt, it was reported, was told that he was only one of two resources ministers in the Morrison government and so did not have the authority to green light the project himself.

“There was no doubt it was unusual,” Mr Pitt said on Monday.

Another former Liberal PM, Malcolm Turnbull, articulated the concerns of many about how and why such a departure from the norms of Westminster parliamentary government occurred. 

“It’s fundamental that if anyone is appointed a minister, or with the responsibilities of a minister, it should be public,” Mr Turnbull told The New Daily.

During his government’s second ministry, the most recent before the Morrison era, Mr Turnbull was temporarily sworn in as minister for agriculture and water resources when then minister Barnaby Joyce stepped down during the dual citizenship crisis.

That was announced to the media and made official by a public swearing in.

Constitutional law expert Anne Twomey from the University of Sydney said of Mr Morrison’s arrangements: “It seems very odd.”

Nationals leader David Littleproud said, perhaps ironically, it was “pretty ordinary” for Mr Morrison’s Coalition partner to have been left out of the loop.

Mr Albanese has promised an inquiry, seemingly confirming that the revelations have left absolutely everyone wrong footed.

On Monday afternoon, a spokesman for Governor-General David Hurley confirmed Mr Morrison had held additional ministries but said processes consistent with the constitution had been followed and any publicity about the arrangements was a matter for the government of the day.

“It is not uncommon for ministers to be appointed to administer departments other than their portfolio responsibility,” a statement from Government House read.

“These appointments do not require a swearing-in ceremony.”

There were conflicting reports about whether one of the former colleagues who shared a portfolio with Mr Morrison, the then finance minister Mathias Cormann, was aware of the arrangement.

Sky News reported that Mr Cormann, at that time one of the government’s most powerful ministers, did not know that he and Mr Morrison held the portfolio simultaneously.

Mr Cormann, who now lives in Paris as head of the OECD, did not immediately respond to a text message from The New Daily seeking clarification.

“This is quite extraordinary. Australians need a prime minister who is focused on the job that they’re given,” Mr Albanese said in Melbourne.

“Nothing about the last government was real, not even the government itself.”

Mr Morrison’s unprecedented move was in response to emergency measures under biosecurity laws and ensured he could administer the  finance and health powers of Mr Cormann and then health minister Greg Hunt, the News Corp journalists’ book argues.

But Mr Albanese said it was contrary to the Westminster system of government, Mr Albanese said.

“The people of Australia were kept in the dark as to what the ministerial arrangements were – it’s completely unacceptable,” he said.

“We have a non-presidential system of government in this country, but what we had from Scott Morrison is a centralisation of power, overriding of ministerial decisions and all done in secret.”

“This is a shambles and it needs clearing up.”

“The Australian people deserve better than this contempt for democratic processes and for our Westminster system of government, which is what we have seen trashed by the Morrison government.”

On Monday afternoon, Department of the Prime Minister and Cabinet secretary Glyn Davis was seeking legal advice about the secret appointments from the Solicitor-General.