Christian Porter's lawyer says he was blindsided by an account of a crucial meeting by Macquarie Group managing director James Hooke sent to him "in an act of desperation" over the weekend.
What was discussed in the November 20 meeting between Mr Hooke, Jo Dyer, Mr Porter's silk Sue Chrysanthou and other lawyers is at the core of a push to remove Ms Chrysanthou from representing Mr Porter in his defamation lawsuit against the Australian Broadcasting Corporation and journalist Louise Milligan.
Ms Dyer says she shared confidential information with Ms Chrysanthou in the meeting, which was convened to discuss an article in The Australian which was critical of Ms Dyer's appearance in a Four Corners program.
She says Ms Chrysanthou could use that information against her, or to Mr Porter's advantage, in the defamation case.
Both Ms Dyer and Mr Hooke were friends of "Kate", the woman whose rape allegations against Mr Porter are at the centre of the defamation proceedings.
The now-industry, science and technology minister says the ABC defamed him by publishing the existence of the allegations.
The defamation case is frozen until after the three-day hearing in the Federal Court about whether Ms Chrysanthou is restrained from acting for Mr Porter.
Ms Dyer's lawyers want to tender an affidavit of Mr Hooke that describes what he remembers being said in the meeting, the court heard on Monday.
But Mr Porter's lawyer, Christopher Withers SC, says the evidence has left him blindsided as it's the first time Ms Dyer has sought to detail what was said in the meeting, rather than just the broad topics canvassed.
He's objecting to Mr Hooke's evidence, which he received at 8.30am on Saturday, being taken into consideration. He says it came too late and leaves Mr Porter at a disadvantage in the litigation.
Mr Withers said on Monday that the confidentiality claim is a "storm in a teacup".
Ms Chrysanthou had only a "short discussion" with Ms Dyer that was confined to the topic of the article in The Australian.
Ms Dyer's legal team has never told him what the confidential information discussed in the meeting was, he said.
That's why, "in an act of desperation", they produced Mr Hooke's affidavit at the last minute, he said.
The court heard on Monday that multiple lawyers indicated Ms Chrysanthou had a conflict of interest and should not act for Mr Porter, before the dispute spilled over into public view.
Her friend and colleague, defamation barrister Matthew Richardson, told her in person and then in an email that she should return the brief, Ms Dyer's lawyer Michael Hodge QC said.
Leading silk Nick Owens SC wrote an opinion concluding that Ms Chrysanthou had a conflict of interest as well, Mr Hodge said.
Ms Dyer raised her objection to Ms Chrysanthou representing Mr Porter on the same day he lodged his statement of claim to start the case in March.
Ms Chrysanthou is represented in the dispute but is not making submissions.
Ms Dyer and Mr Hooke will be cross-examined on Monday.
Ms Chrysanthou will have her turn in the witness box on Tuesday, as will Mr Porter's solicitor in the defamation proceedings, Rebekah Giles.
