During the Covid-19 pandemic, Morrison appointed himself minister of the departments of health, finance, industry, science, energy and resources, treasury and home affairs, without the knowledge of the appointed ministers.

An “angry, hurt, confused, dumbstruck” Frydenberg has told author and Nine newspapers columnist Nikki Savva his leader still hasn’t apologised for his actions.

“I don’t think there was any reason for Scott to take on the additional Treasury portfolio,” he told Savva, according to an extract from her upcoming book on the Morrison regime published on Friday.

“The fact he did take it, and it was not made transparent to me and others, was wrong and profoundly disappointing.

“It was extreme overreach.”

Former High Court judge Virginia Bell was asked by Labor Prime Minister Anthony Albanese on August 26 to inquire into the portfolios issue, after the solicitor-general found Morrison’s action had “fundamentally undermined” the principles of responsible government.

Albanese asked for the inquiry to explore how and why the action was taken and who knew about it.

The solicitor-general found it was “impossible for the parliament to hold ministers to account for the administration of departments if it does not know which ministers are responsible for which departments”.

Morrison appointed himself to administer the departments of health; finance; industry, science, energy and resources; treasury; and home affairs.

Bell was also asked to look at the implications arising from the appointments for the functioning of departments and for accountability and public confidence in government.

She will make recommendations to the government on any changes which could provide greater transparency and accountability.

The government has pledged to start work on implementing any recommendations as early as next week.

Deputy Liberal leader Sussan Ley dismissed reports the coalition had determined to downplay the severity of Morrison’s actions and said it would support closing the loophole that was exploited.

She did not comment on reports the former prime minister refused to be interviewed for the inquiry.

“The important thing is what the current Liberal leadership has said about those events and what might happen going forward and we absolutely are committed to dealing with it,” she told ABC Radio.

“If legislative change is required we will support it.”

Former Liberal prime ministers John Howard, Tony Abbott and Malcolm Turnbull have all expressed concerns about Morrison’s action.

The health and finance portfolio roles began in March 2020, while he started as industry minister in April 2021, and home affairs and treasury in May 2021.

He justified the action by saying the only time he used his extra powers was in vetoing the PEP11 resource exploration project off the NSW coast.

Morrison intended the powers to be used only in extreme circumstances “due to incapacity or in the national interest”.

They had not been made public because there was no consistent process for publication, he said, but in any case, the authorities were legally valid.

“I can only state that I took the decisions I did as prime minister with the best of intentions to do all I could to protect Australia in the face of multiple crises,” he said in a statement in August.