SYDNEY: Australia's Prime Minister Anthony Albanese has sought legal advice following reports that his predecessor Scott Morrison was secretly appointed to key ministerial roles during the COVID-19 pandemic, duplicating some portfolios.

Ministers are traditionally sworn in at a ceremony by the governor-general, but that did not happen in the case of the additional roles, and Albanese said it was unprecedented that key cabinet members were not aware of the appointments.

"This was a centralisation of power by the former Prime Minister," Albanese, who has sought advice from the solicitor-general, Australia's second law officer, told reporters on Monday.

"This isn't some, you know, local footy club," he added. "This is a government of Australia, where the people of Australia were kept in the dark as to what the ministerial arrangements were."

Morrison, who was prime minister from 2018 to 2022, did not respond to a request for comment.

In an emailed statement, the governor-general's office told Reuters the appointments were valid under the constitution, did not require a swearing-in ceremony, and added that publicising them 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," the spokesperson for the governor-general's secretary said.

The governor-general followed normal process and acted on the government's advice in appointing Morrison to administer portfolios besides his own department and the cabinet, the spokesperson added.

The Australian newspaper said Morrison was appointed health minister in 2020, alongside Health Minister Greg Hunt, to avoid concentrating power in one person when biosecurity emergency powers were adopted to tackle the coronavirus pandemic.

He was later also appointed finance minister and resources minister. Former resources minister Keith Pitt told broadcaster ABC the situation was "unusual" and he was "concerned" when he was told Morrison shared his responsibilities in 2021.

Morrison later blocked an offshore gas project.

David Littleproud, the leader of the National party, the coalition partner of Morrison's Liberals, told ABC the news was "disappointing", and added that the cabinet should be trusted.

It was not immediately clear what the implications were for the Liberal party's coalition with the National party.

"These revelations do raise into question our Westminster system of government," said Bridget McKenzie, the National leader in the upper house.

"Who is the senior minister, what if they disagreed?" she asked the ABC.