"It was the weirdest phone call I've ever had in my life," Brittany Higgins told the ACT Supreme Court on Thursday, when she gave evidence in the jury trial of alleged rapist and former Liberal Party colleague Bruce Lehrmann.

Lehrmann has pleaded not guilty to a charge of engaging in sexual intercourse without consent.

He denies allegations he raped Ms Higgins in the office of Senator Linda Reynolds, for whom the pair worked at the time, in March 2019.

The court heard on Thursday that a few months after the alleged rape, Ms Higgins moved into a role as an assistant media adviser to Senator Michaelia Cash.

She claimed she and Senator Cash had "many conversations" about the alleged sexual assault prior to January 2021, when Ms Higgins, having just met with journalist Lisa Wilkinson in preparation to tell her story, resigned from her position.

Senator Cash, the minister for employment, skills, small and family business at the time, subsequently phoned Ms Higgins and offered her alternatives to leaving.

On Thursday, Ms Higgins described the call as "so strange".

"The entire call, she was pretending like she didn't know [details of the alleged rape] and that she thought a security guard assaulted me," Ms Higgins said.

"Like, it was ridiculous."

Asked by Lehrmann's barrister, Steven Whybrow, if she had recorded the call without Senator Cash's knowledge, Ms Higgins replied: "That's correct."

She also agreed she had sent it to a friend named Emma Webster, now a public relations consultant, within 15 or 20 minutes, saying she did this "for safekeeping".

"I don't know why I had this unfounded belief that I would, like, lose recordings," Ms Higgins told the court.

"But I was just trying to give them to as many people as possible to have them, just so that they existed, because it's my word against a cabinet minister's.

"The disparity between those two powers is ridiculous and so I was trying to give it to as many friends just to be like, 'Please, can you hold onto this for me?'"

Ms Higgins also said that, a day after her initial meeting with Ms Wilkinson and a day before tendering her resignation, she covertly recorded a conversation with Senator Cash's chief of staff, Daniel Try.

She then sent the audio to a journalist, Samantha Maiden, "for corroboration".

"I didn't think anyone would believe me, so I needed to have him say it himself," Ms Higgins told the court.

"That (a) he knew about the assault, (b) that they knew about it in 2019, and (c) that Michaelia Cash knew, and all of that is in that audio."

Mr Whybrow is set to continue cross-examining Ms Higgins on Friday.