It was revealed on Tuesday the former prime minister had secretly appointed himself to the finance, treasury, health, home affairs and resources portfolios between March 2020 and May 2021.
Prime Minister Anthony Albanese is seeking advice from the solicitor-general on whether Mr Morrison's actions have any legal implications.
Mr Morrison told reporters in Sydney on Wednesday he had sworn himself into the extra portfolios as a means to deal with the extraordinary circumstances brought on by the COVID-19 pandemic.
But he admitted there was another reason, unrelated to the pandemic, to take on the resources portfolio - to enable him to reject the PEP-11 gas exploration licence.
"I don't regret that for a second, and I don't think anyone who went surfing off the New South Wales coast this week - up around Newcastle, or the Central Coast, or off the Northern Beaches - would take any issue with a prime minister who lived up to his word and considered this matter from first principles," he said.
"It's about the prime minister making a decision in the national interest and protecting our environment.
"I suspect the people who live on the New South Wales Central Coast, and Hunter Coast, and the Northern Beaches of New South Wales, will be forever grateful."
The decision is now the subject of a Federal Court appeal.
Local surfers have called on Mr Albanese to honour his pre-election commitment to rule out the gas exploration licence.
Former resources minister Keith Pitt said on Monday he would not comment on the court matter, but that he discharged his responsibilities in accordance with ministerial standards, the cabinet handbook and legislation.
