The case of a former political adviser accused of raping a colleague inside Australia's Parliament House has been aborted after juror "misconduct".

Bruce Lehrmann, 27, denies sexually assaulting Brittany Higgins on a government minister's sofa after a night out in Canberra in 2019.

He says they did not have sex at all.

But after a 12-day trial and five days of deliberation the jury was discharged when it emerged one member had looked at academic research on sexual assault.

Juries are required to reach a verdict only on evidence presented in the courtroom.

The research was discovered by a court official during "routine tidying" of the jury room, Justice Lucy McCallum told a court.

"It may be that no harm has been done, but that is not a risk I can take," the judge said, adding she had previously warned the jury at least 17 times.

It is not yet clear if there will be a retrial, but Justice McCallum set aside a date in February in the event one goes ahead.

Before giving her account to police in early 2021, Ms Higgins gave up her right to anonymity and went public with her claims in high-profile newspaper and television interviews.

Her allegations were a catalyst for what's been called Australia's "Me Too moment", sparking huge protests over the safety of women, particularly in politics.

Speaking outside court on Thursday, Ms Higgins criticised the justice system and said the trial had taken a toll.

"I told the truth, no matter how uncomfortable or unflattering, to the court," she said. "My life has been publicly scrutinised, open for the world to see."

Mr Lehrmann's legal team said they were disappointed by the outcome, but said it would be inappropriate to comment further.

They also argued "a pre-prepared speech" by Ms Higgins outside court could prejudice a future retrial, saying they had referred it to police and the court for investigation.

The trial heard that Mr Lehrmann and Ms Higgins worked in the same office - for then-Defence Industry Minister Linda Reynolds. On 22 March 2019, they both had drinks with colleagues and others.

Ms Higgins said she was the most intoxicated she'd been in her life, after spending hours at two Canberra bars, before the pair shared a cab to Parliament House, the jury was told.

Ms Higgins says she fell asleep on a sofa in Ms Reynolds's office and woke to find Mr Lehrmann having sex with her.

In a police interview played to the jury, she said she had cried while telling Mr Lehrmann "stop" and "no".

She reported the alleged rape to police in the days afterwards but then did not proceed with her complaint because she was afraid she might lose her job, the jury heard.

Mr Lehrmann chose not to give evidence, but in a police interview that was played to the court said what was alleged "simply didn't happen".

His lawyer, Steven Whybrow, argued parts of Ms Higgins' evidence were "totally and utterly inconsistent".

"We can't be satisfied beyond a reasonable doubt that she knows what happened," he said.

The aborting of the trial comes two days after jurors told the court they had been unable to reach a unanimous decision but were asked by the judge to try again.

The prosecution and defence teams are yet to make arguments about whether the case should be retried.

If a retrial in February goes ahead, it will mark two years since Ms Higgins first went public with her allegations.

Her interviews last year reignited - yet again - criticisms of Australian politics as a hostile workplace.

It also sparked massive protests last year when more than 100,000 people gathered in towns and cities across Australia to voice their fury about sexism, misogyny and abuse in society.

It also led to a damning review which found that a third of employees in federal parliament had been sexually harassed.

There had been concerns that Mr Lehrmann might not get a fair trial because of the publicity, but an earlier application for it to be thrown out was rejected.