Chief Justice Lucy McCallum said it had been discovered a juror had undertaken some research in relation to the case which had entered the jury room.
Bruce Lehrmann was being tried by the ACT Supreme Court, charged with sexual intercourse without consent.
He pleaded not guilty.
The jury was dismissed following a 12-day trial and had undertaken a little more than five days of deliberations.
The chief justice is preparing to outline her reasons.
On Wednesday, Ms McCallum revealed details of Lehrmann's previous attempt to delay or permanently halt the case.
Lawyers for the accused cited former prime minister Scott Morrison's parliamentary apology to women as reason for a delay, arguing it disadvantaged his case.
The then-prime minister apologised directly to Ms Higgins - who was sitting in the public gallery - for the "terrible things" that had happened in parliament.
"The place that should have been a place of safety and contribution turned out to be a nightmare," he said.
"I'm sorry for all those who came before Ms Higgins and endured the same. But she had the courage to stand, and so here we are."
Chief Justice McCallum said the defence had argued the case was unique because Ms Higgins "walks into court with an aura about her" and that the problem this created was "incurable".
She did not accept the application.
On Tuesday, the jury sent a note to the court indicating it was unable to reach a unanimous verdict on the rape allegation.
But the chief justice asked them to return to their deliberations, saying experience shows juries are able to reach a decision if given more time.
She asked them to calmly and objectively listen to each other's opinions and try to reach a unanimous decision.
But she reminded them they could not join in a verdict if they did not "honestly and genuinely" think it was the correct one.
Earlier this week the jury asked for a "little extra time" to consider their verdict and were told there was no time pressure on them.
"There's no rush. There's no time limit," Chief Justice McCallum said.
Ms Higgins alleges Lehrmann raped her in the parliamentary office of Linda Reynolds when they worked for her as defence industry minister in March 2019.
He denies any sexual interaction.
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