After more than two weeks hearing evidence from 29 witnesses, as well as arguments from lawyers for the prosecution and for alleged rapist Bruce Lehrmann, the jury of eight women and four men commenced deliberations on Wednesday afternoon.

Lehrmann, 27, has been on trial in the ACT Supreme Court since October 4, having pleaded not guilty to a charge of engaging in sexual intercourse without consent.

He denies taking part in any sexual activity with Ms Higgins in the ministerial office of their boss at the time, Senator Linda Reynolds, after "a drunken night out" in March 2019.

Defence counsel Steven Whybrow finished his closing address to the jury early on Wednesday, claiming there were at least 325,000 reasons Ms Higgins had pushed ahead with a rape allegation based on what he described as "reconstructed" memories.

The number was a reference to Ms Higgins having been offered a $325,000 deal to write a book about her experiences as a Liberal Party staffer.

Mr Whybrow said it was his case that while Lehrmann and Ms Higgins had entered Senator Reynolds' suite together when the pair arrived at Parliament House in the early hours of the morning in question, only the latter went into the politician's actual office.

Security guard Nikola Anderson has described subsequently seeing Ms Higgins on a couch in that room, naked and passed out, after Lehrmann had left Parliament House alone.

"The $64,000 question, or perhaps in Ms Higgins' case the $325,000 question, is do you accept what Ms Higgins says happened?" Mr Whybrow asked jurors.

"[Do you accept] that he went in there and sexually assaulted her? In my submission, ladies and gentlemen, you'd have a reasonable doubt about that."

Having started his closing address on Tuesday by arguing Ms Higgins "doesn't know what happened", Mr Whybrow continued trying on Wednesday to cast doubt on her memory.

He cited Ms Higgins saying she thought she had dealt with two male security guards when one was in fact female, as well as a comment she had made about her recollection of signing something at the entrance to Parliament House perhaps being "a built memory".

Recapping Ms Higgins' evidence, Mr Whybrow told jurors she had made "very few statements ... that have not been demonstrated to be suspect".

He again claimed Ms Higgins had been motivated to fabricate a rape allegation when, three days after the alleged sexual assault, she learned the security guard had seen her in a state of undress in Senator Reynolds' office.

Mr Whybrow noted a text Ms Higgins had sent former boyfriend Ben Dillaway soon after being told this, describing how she had expressed fear for her job, and saying that message was "where all this starts".

He suggested Ms Higgins had subsequently decided against pursuing a formal complaint with police because she did not lose her job and indeed went to work for another Liberal senator, Michaelia Cash.

Everything seemed to be "going swimmingly", he said, until an enquiry from The Canberra Times in October 2019 once again brought up what had happened in Senator Reynolds' office seven months earlier.

Ms Higgins ultimately resigned from her job with Senator Cash in January 2021, before taking part in media interviews about the alleged rape and pursuing a formal complaint with police the next month.

Mr Whybrow told jurors he was not in court to tell them why Ms Higgins had decided to take that course at that time, but he offered a suggestion as to why she had since continued to press the rape allegation.

"It's a trite line but there are 325,000 reasons, at least now, why this case is important from her perspective," he said.

Jurors had previously heard contrasting arguments put forward by prosecutor Shane Drumgold SC, who used his closing address on Tuesday to describe Ms Higgins as "an inherently credible witness".

Mr Drumgold told jurors Ms Higgins had appropriately acted with caution before deciding to pursue a police complaint, arguing she had been "a young lady in the middle of strong political forces".

He said she had been "faced with a fork in the road" in the aftermath of the alleged rape, and forced to choose between reporting it and becoming a political problem or keeping her "dream job" in parliament.

Chief Justice Lucy McCallum summed up the case for the jury, which initially had 16 members, and provided legal directions at the conclusion of both sides' closing arguments.

Four members of the jury then had to be "voted off the island", as the judge put it, leaving 12 to commence deliberations just before 3pm on Wednesday.

The ACT's top judge warned the jury not to be "swayed by public opinion" while striving to reach a unanimous verdict, noting the case had attracted considerable news coverage.

"You will have seen the number of journalists in court each day," Chief Justice McCallum said.

"They're practically hanging from the rafters, members of the jury."

The jury will continue deliberating on Thursday.

MORE COVERAGE OF THE TRIAL: