“In the abundance of caution and to avoid any perception of conflicts of interest that may arise, the attorney-general when he returns will not perform certain functions of his office that may relate to the Federal Court or the ABC,” Mr Morrison told parliament on Tuesday.
Labor has raised concerns the defamation action will be used as an excuse for the government to dodge questions about the issue.
Senior opposition MP Tanya Plibersek signalled the court action wouldn’t stop calls for a separate investigation into the allegations.
“What really worries me is that this will be used as an excuse for the government not to have an inquiry and to stop answering questions about the Christian Porter matter,” she told ABC radio.
Ms Plibersek said it was nonsense for the government to suggest an independent inquiry would offend the rule of law.
The minister identified himself as the subject of the article almost two weeks ago.
His lawyer Rebekah Giles said he was forced to go public after a series of news articles, social media posts and interviews made him “easily identifiable to many Australians”.
The statement of claim lodged in the Federal Court in Sydney says Mr Porter’s character and reputation was gravely injured as a result of the story.
Voters are slightly in favour of an independent inquiry with 55 per cent agreeing further investigation is needed to determine Mr Porter’s fitness to serve as attorney-general.
A new Essential poll found 45 per cent believe the matter should be closed because police are not pressing charges.
People are split on whether an inquiry would undermine the rule of law, as Mr Morrison claims.
The survey of 1124 people found 37 per cent agree, 33 per cent disagree and 31 per cent are undecided.
Mr Porter’s lawyers claim journalist Louise Milligan acted with malice because she knew it was impossible for criminal or civil guilt to be proved.
The attorney-general is seeking aggravated damages, costs and removal of the article and related material on the web.
Lawyer Michael Bradley, who represented the alleged victim before she died, believes the defamation action will be a challenging case for Mr Porter.
“The bar is fairly high for the plaintiff to establish where they weren’t named they were actually clearly identifiable to the audience,” the Marque Lawyers managing partner told Sky News.
Mr Bradley said the case would rest on whether a casual reader rather than political aficionados would know the unnamed minister was the attorney-general.
Mr Morrison told parliament it was appropriate the matter be considered in a court of law.
No date has been set for an initial hearing.