Nationals senator Bridget McKenzie says the former prime minister's decision showed "complete disrespect" for her party.

"Our coalition arrangements are a negotiated outcome and they include a ratio of cabinet portfolios in a coalition government," she told ABC Radio National on Thursday.

"By essentially removing the authority of one of those ministers and giving it to a Liberal minister ... (he) breached the coalition agreement.

"It showed complete disrespect for the second party of government ... the National Party would not have agreed with having one of its ministers removed."

Mr Morrison secretly appointed himself to the finance, treasury, health, home affairs and resources portfolios between March 2020 and May 2021.

The former leader phoned his former ministerial colleague Karen Andrews on Thursday morning to apologise, AAP understands.

Mr Morrison had previously personally apologised to former treasurer Josh Frydenberg and former finance minister Mathias Cormann for keeping his appointments to their portfolios secret, but not to Ms Andrews.

Ms Andrews was the first Liberal to call for the former prime minister to resign from parliament, after he addressed the media on Wednesday saying he took over the five portfolios in secret in the national interest.

"I made my statements a couple of days ago and I assure you I have not changed my views," she told Sky News.

"It's good we've had the line drawn in the sand by (Opposition Leader) Peter Dutton. He has made it clear that would not happen if he were to be elected."

While Ms Andrews has no problem with contingencies being put in place, she said she did not understand the need for secrecy.

"Transparency is incredibly important," she said.

"If you put in place contingencies, that's a good thing ... but they needed to be done in a matter of good governance."

Mr Dutton said he would have told his former leader it was "inappropriate for him to be assuming these powers" had he been consulted at the time.

"Most people want to move on and start dealing with issues that are more important, the rising cost of living," he said.

"He's apologised for it, he's no longer occupying the office and there's not much more you can continue to trail over it."

Meanwhile, Governor-General David Hurley has revealed he had "no reason to believe" Mr Morrison would not make the appointments public knowledge.

Mr Morrison on Wednesday said he kept the roles confidential as he did not want to "undermine the confidence of ministers in the performance of their duties".

He said he only used the extra powers once, to block a gas drilling project off the NSW coast.

That decision, made in 2021, is the subject of a Federal Court appeal.

Nationals MP Keith Pitt held the resources portfolio at the time.

Prime Minister Anthony Albanese is seeking advice from the solicitor-general on whether his predecessor's actions have legal implications.

Home Affairs Minister Clare O'Neil said her office is checking for any other decisions that could have been made by Mr Morrison.

Australian Associated Press