The Prime Minister is demanding an explanation amid reports his predecessor secretly swore himself into three ministry positions.

Former deputy prime minister Barnaby Joyce claims Mr Morrison was sworn in as a second resources minister in December last year.

The then-prime minister reportedly proceeded to use his powers to stop controversial gas projects slated for the NSW coast.

The report comes as a new book, Plagued, by Simon Benson and Geoff Chambers, claims Mr Morrison also swore himself into the health and finance portfolios.

“This is extraordinary and unprecedented,” Anthony Albanese told the press in Victoria this morning.

“Australians knew during the election campaign that I was running a shadow ministry.

“What they didn’t know was that Scott Morrison was running a shadow government, a shadow government that was operating in the shadows.

“What we had from Scott Morrison is a centralisation of power, is overriding of ministerial decisions, and all done in secret! All done in secret!”

Mr Albanese said he is waiting on advice from the Solicitor-General as to whether any laws had been broken.

“I’ll accept that advice and we will operate in a transparent way and I’m sure tomorrow, in Canberra, I will have more to say about that.”

He expects to receive a full briefing on the matter this afternoon.

Press PLAY below to hear audio from the PM’s press conference

Image: Mark Santomartino / Twitter