"The last couple of years have been difficult and unrelenting," friend Emma Webster said in a statement.

"While it's disappointing the trial has ended this way, Brittany's health and safety must always come first.

"Brittany is extremely grateful for all the support she has received, particularly from our mental health care workers."

Ms Higgins, a former Liberal Party staffer, accused ex-colleague Bruce Lehrmann of raping her at Parliament House when the pair worked together for Senator Linda Reynolds.

Mr Lehrmann, 27, pleaded not guilty to a charge of sexual intercourse without consent.

He has always denied engaging in any form of sexual activity with the alleged victim on March 23, 2019, when the pair went back to the minister's parliamentary suite after a drunken night out.

The public spotlight on Ms Higgins and Mr Lehrmann was immense when the latter stood trial in October, with Chief Justice Lucy McCallum quipping that journalists were "hanging from the rafters".

ACT Director of Public Prosecutions Shane Drumgold SC referred to the intense scrutiny on Friday, when he announced his decision to discontinue the case against Lehrmann.

Mr Drumgold made this call after considering what he described as "compelling" medical evidence, which indicated Ms Higgins' life would be at risk if the case was to continue.

"During the investigation and trial as a sexual assault complainant, Ms Higgins has faced a level of personal attack that I have not seen in over 20 years of doing this work," he said.

"She has done so with bravery, grace and dignity, and it is my hope that this will now stop and Ms Higgins will be allowed to heal."

Prior to Mr Drumgold declining to proceed with the case, Mr Lehrmann had been scheduled to face a retrial commencing on February 20, 2023.

The retrial was listed after a rogue juror brought independent research into the jury room during deliberations at the first trial, causing Chief Justice McCallum to declare a mistrial.