An inquiry will be held into former prime minister Scott Morrison's decision to appoint himself to multiple ministries, after government legal advice said it was "inconsistent" with constitutional conventions.
Prime Minister Anthony Albanese on Tuesday released advice from the solicitor-general on the legal implications of Mr Morrison's decision to secretly swear himself into five ministries.
While the advice said Mr Morrison was validly appointed to the role of resources minister in April 2021, it said the secrecy surrounding the appointment was unusual.
"(That) the parliament, the public and the other ministers who thereafter administered (the resources department) concurrently with Mr Morrison were not informed of Mr Morrison's appointment was inconsistent with the conventions and practices that form an essential part of the system of responsible government," the advice said.
"It is impossible for parliament and the public to hold ministers accountable for the proper administration of particular departments if the identity of the ministers who have been appointed to administer those departments is not publicised."
The solicitor-general's advice said the governor-general had no discretion to refuse the then-coalition prime minister's advice to appoint him as minister.
Mr Albanese said the inquiry into Mr Morrison's actions would be standalone, and not woven into an examination of decisions taken during the pandemic.
"It needs to be not a political inquiry but an inquiry with an eminent person with a legal background to consider all of the implications," he told reporters in Canberra on Tuesday
"We will make a future announcement about an inquiry. I am giving notice today that that inquiry will take place. This isn't something that can be just dismissed."
The prime minister said the inquiry would also look at reform to ensure secret appointments could not take place again.
The solicitor-general's advice also recommended changes, including altering the form of published ministry lists to include all appointments and responsibilities.
"The government could require, as an administrative practice, the website of each department to list all of the ministers who have been appointed to administer that department," the advice said.
"Further or alternatively, a practice could be adopted of publishing in the gazette all appointments made under section 64 of the constitution."
Mr Albanese said he asked the Department of Prime Minister and Cabinet to work with the Governor-General's office to adopt the practice of gazetting all future appointments.
"We will also give further consideration to whether any further immediate changes are required," he said.
"One of the things we will need to consider is any future legislative changes to make sure that that is enshrined, to make sure that it is not dependent upon the goodwill of the government of the day."
The prime minister said the government had not yet made a decision whether to support a possible censure motion of Mr Morrison in parliament during the next sitting week.
Earlier on Tuesday, Deputy Prime Minister Richard Marles said regardless of the findings Mr Morrison should face repercussions.
"There needs to be some political consequence for a person who has flouted the Westminster cabinet system so completely," he told ABC News.
"It needs to be a severe consequence, because what we saw was a total undermining."
Mr Morrison intervened as co-resources minister, by blocking the PEP-11 gas exploration licence off the NSW coast after then-resources minister Keith Pitt approved the project.
The final decision is now the subject of a Federal Court appeal.
Mr Morrison has maintained that was the only time he used his powers to interfere in the portfolios.
