Senator Linda Reynolds' chief of staff when Brittany Higgins was allegedly raped in parliament may not be able to give evidence to the politician's high-profile defamation trial with her former staffer.
The former defence minister is suing Ms Higgins over a series of social media posts containing alleged mistruths she believes damaged her reputation.
The West Australian Supreme Court on Wednesday heard lawyers in the defamation battle were assessing a medical report about Fiona Brown's fitness to testify.
"(We) need to evaluate the report to determine the likelihood of being in a position to call Ms Brown next week," the senator's lawyer Martin Bennett told the court.
Mr Bennett said an alternative could be to use Ms Brown's evidence from Bruce Lehrmann's failed defamation case against Network Ten.
The court has previously been told Ms Brown spoke to Ms Higgins after her alleged rape and took notes about how it was handled.
She was also present when the senator met with her former staffer in the same office the alleged sexual assault took place.
Former media adviser to the retiring senator, Nicole Hamer, recalled working with Ms Higgins for weeks on the senator's campaign in Perth for the 2019 federal election after the incident.
She said Ms Higgins attended events and celebrations, and helped at letterbox drops and polling booths when she alleges she was "isolated, traumatised, depressed, unsupported and confused".
Ms Hamer said Ms Higgins had multiple sick days and was occasionally "absent from the office" during the campaign.
She said she was told Ms Higgins was unwell but she wasn't concerned about her and didn't make inquiries about her wellbeing.
Ms Hamer also recalled being "definitely surprised" when news of Ms Higgins' alleged rape and her claims about a political cover-up broke in the media in 2021.
Ms Hamer also said she overheard Senator Reynolds call Ms Higgins a lying cow while watching her tearful interview on The Project.
"I believe it was words to that effect," she said.
She also recalled the senator telling staff a few days later the comment wasn't made about the rape but Ms Higgins' allegations about her alleged mishandling of it.
Ms Hamer said the senator called Ms Higgins a liar a second time about a week later when she returned to her office from parliament question time in a distressed state.
She said the first time she heard about the late-night security breach in the senator's ministerial suite involving Ms Higgins and Lehrmann was in late 2020 when the office of then home affairs minister Peter Dutton received a media inquiry about it.
"I wasn't aware of the nature of it," she said, when asked if she knew it involved allegations of sexual assault.
"I just was made aware that the (Australian Federal Police) were investigating an incident."
Mr Bennett tendered witness statements for Senator Reynolds' parents, Laith and Janice Reynolds, to the court.
"They very much desired to publicly give their evidence ... It would put a strain on, particularly on Ms Reynolds to do so," he said.
Lehrmann has always denied sexually assaulting Ms Higgins and his criminal trial was derailed by juror misconduct.
