Former Treasurer Josh Frydenberg, who left politics after losing his seat in the May election, was also unaware Morrison held responsibility for treasury, The Australian newspaper reported.
Liberal Opposition leader Peter Dutton said legal services from the solicitor general was needed before any decisions on next steps were made.
In an extended statement, Morrison, who remains a Liberal backbencher, said he regretted that his actions had caused concern but he previously acted in good faith in an emergency.
Morrison defended dealing with extra ministerial roles without his cabinets knowledge through the COVID-19 pandemic, saying it had been an unprecedented time and that the powers served as a safeguard.
I used such powers using one occasion only. I did so not seek to hinder Ministers in the conduct of these portfolio, he said in the statement.
He added that in hindsight these arrangements were unnecessary.
Morrison said in a radio interview previously Tuesday he didnt make the arrangements public since they were a safeguard only, also it was an oversight the ministers werent informed their roles were duplicated.
We’d to take some extraordinary measures to place safeguards set up, he told radio station 2GB, likening it to presenting two keys on a nuclear submarine.
The resources minister role he took on in 2021 was different, he said, because he previously used the energy to avoid approval for a gas exploration project off the coast of Australia that was opposed by local communities. Your choice has been challenged in court.
I really believe I made the proper decision in the national interest. This is the only real matter I involved myself directly with in this or any Department, he said in the statement.
Albanese said it had been concerning that two different people had responsibility for the resources portfolio and had different positions on matters.
Not tabling in parliament who was simply in charge of ministerial portfolios was an extremely clear breach of the obligations that the prime minister must the parliament, he told ABC radio previously Tuesday.