A prominent constitutional lawyer says revelations former Prime Minister Scott Morrison swore himself into five portfolios is a "bizarre and strange thing to do", given Governor-General David Hurley is able to appoint two ministers to the same portfolio.

"The Governor-General acts on advice, he has no choice but to act on it... so in a funny way, the most important thing about this is that Morrison seems to have succeeded in embarrassing the Crown, which is almost the first duty of a minister not to do," Professor Greg Craven, vice chancellor of Australian Catholic University, told Liam Bartlett on 6PR Mornings.

“Turns out he was the world’s first stealth bulldozer.”

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