Brittany Higgins’ mental health forces case closure.

Concerns about the health of former Liberal Party staffer Brittany Higgins have forced the case against Bruce Lehrmann, the man who was accused of raping her at Parliament House, to be abandoned.

ACT Director of Public Prosecutions Shane Drumgold announced this morning that the sexual assault charge against Lehrmann will be dropped, because of an "unacceptable risk to the life of the complainant".

A new trial date of February 20 had previously been set after the jury in the trial was discharged because of misconduct by one member.

During the first trial, Lehrmann pleaded not guilty to a single count of rape and denied that any sexual activity occurred.

Drumgold said that, during the investigation and trial as a sexual assault complainant, Higgins had faced a level of personal attack he had never seen.

"Whilst the pursuit of justice is essential for both my office and for the community in general, the safety of a complainant in a sexual assault matter must be paramount," he said.

Higgins has confirmed she is receiving mental health treatment through a Queensland hospital.

Almost  90% of sexual assault victims never bring a case to the police and a tiny minority get their day in court.