Christian Porter and Sue Chrysanthou SC, Sydney defamation expert, may potentially pay costs to the tune of half a million dollars after losing a legal battle with Jo Dyer, a friend of the woman who accused the federal Liberal minister of rape.

Ms Dyer, a theatre/film producer and fetival director, won Federal Court proceedings to stop Ms Chrysanthou from acting on Mr Porter’s behalf in his defamation proceedings against the ABC.

The hearing in the Federal Court on Tuesday put Ms Dyer’s costs at an estimated $550,000 based on one assessment but Mr Porter and Ms Chrysanthou have queried how that sum was calculated. In the past, Ms Chrysanthou had advised Ms Dyer for free about an article in The Australian which was published after Ms Dyer appeared in ABC’s Four Corners last November. In the telecast, the rape allegation had not been broached.

Justice Tom Thawley had concluded that, as a result, Ms Chrysanthou should be restrained from acting for Mr Porter as there was risk of misuse of confidential information received by Ms Dyer.

Both Ms Chrysanthou and Mr Porter lodged an appeal against that decision as well as on Justice Thawley’s ruling on costs.

READ MORE: Christian Porter and lawyer Sue Chrysanthou ordered to pay Jo Dyer’s legal costs

Ms Chrysanthou’s barrister Anne Horvath, acting for Ms Chrysanthou, requested that Ms Dyer’s lawyers produce timesheets and invoices to help explain the costs.

“It’s not clear to me … exactly what falls within that 550-odd figure,” Ms Horvath said.

“We had thought that the most efficient way forward would be for us to receive the time records. Then, within a very short time, we could indicate whether we oppose going to a lump sum [order].”

Barrister Callan O’Neill, acting for Mr Porter said that the law firm partner acting for Ms Dyer appeared to have spent 120 hours working on the matter, a senior associate spent 220 hours and a junior lawyer had spent 244 hours looking at the matter “in 16 days”.

The timesheets and invoices need to be produced by 5pm on Friday.

In May, Mr Porter agreed to withdraw his defamation case against the ABC, although the proceedings have not yet been officially discontinued. He denies allegations that he raped a young woman in the 1980s when they were both teenagers.

Last year, the woman took her life.