The ACT's top prosecutor does not believe the rape trial of former Liberal Party staffer Bruce Lehrmann was extraordinary and says he maintained objectivity throughout the case.

But he admitted he had "misread" a conversation with Ten Network journalist Lisa Wilkinson about a planned Logies speech ahead of Mr Lehrmann's rape trial.

Director of Public Prosecutions Shane Drumgold gave evidence at the first public hearing of an independent inquiry into how the territory's justice system handled rape allegations made by Mr Lehrmann's ex-colleague Brittany Higgins.

The ACT government established the inquiry after accusations by police and prosecutors about each other's conduct during the case.

Former Queensland solicitor-general Walter Sofronoff is leading the inquiry which is examining how territory police, prosecutors and a victim support service handled Ms Higgins' allegations.

On Monday, Mr Drumgold said his role as a prosecutor was "not to pursue one side of the case over the other" and to make sure a case was "adequately presented before a court in accordance with the law".

He said it was critical for a prosecutor to be objective and failure to do so could cause a miscarriage of justice and erode the community's trust.

Asked if he had ever lost objectivity during the case, Mr Drumgold said he did not believe so.

"(The case) was not extraordinary, in my sense. From my approach, factually, it was like many other trials that I had done," he said.

"There were facets of this trial that meant that I had to be particularly protective of elements ... I had to keep the publicity out of the courtroom, essentially.

"It was a high-profile case. The concern to me was to make sure that a jury weren't influenced by the things that were happening that weren't part of this case."

Mr Drumgold said he made sure to communicate this to the jury, including in his opening statement at the beginning of the trial where he told them to ignore what they thought they knew about the case.

During a pre-trial meeting Mr Drumgold said Ms Wilkinson told him about her Logies award nomination for her 2021 interview with Ms Higgins about the alleged rape.

Ms Wilkinson later won the award and gave a speech which generated intense media reporting about the case, resulting in ACT Supreme Court Chief Justice Lucy McCallum postponing the trial.

Mr Drumgold said he had misread the conversation with Ms Wilkinson, but believed he had cautioned her against giving the speech and that she did not think she would win.

"I entirely misread the situation ... I thought this was somebody telling me that they were up for an award for an interview," he said.

"My words were: 'Look, any publicity could give rise to another stay (application)'. To me that was clear enough."

Mr Lehrmann faced an ACT Supreme Court trial in October 2022 but juror misconduct meant a verdict was not reached.

Prosecutors later dropped the charge against Mr Lehrmann because of concerns about the impact a second trial would have on Ms Higgins' mental health.

Mr Lehrmann denies raping Ms Higgins in Parliament House in 2019.

He made an unexpected appearance at the inquiry on Monday and sat at the back of the tribunal room.

Mr Lehrmann's defence lawyer Steven Whybrow will also give evidence to the inquiry in the first block of public hearings.

A report will be provided to Chief Minister Andrew Barr at the end of July.