Defence Minister Linda Reynolds has apologised for calling Brittany Higgins a "lying cow", after the former Liberal staffer threatened possible legal action over the remarks.
Senator Reynolds reportedly made the comments to staff in her office after Ms Higgins spoke out about her alleged rape in Parliament House.
Lawyer Rebekah Giles, who is acting for Ms Higgins, said a legal letter has been sent to Senator Reynolds, demanding she withdraw her comments and apologise.
In a statement on Friday, Senator Reynolds said she intended to issue an apology to Ms Higgins and expressed remorse for the comments.
"In response to a letter from Ms Higgins' lawyers yesterday afternoon, discussions are now underway through our legal representatives in an effort to resolve this matter as soon as possible, with any resolution to include an apology," she said.
"However, in the meantime, I want to express how deeply sorry I am for these remarks and for any hurt and distress they have caused."
Senator Reynolds is currently on medical leave until next week.
In the legal letter, sent to Senator Reynolds, Ms Giles described the remarks as a “distasteful character assassination”.
“Self-evidently, this demeaning and belittling statement, in which you refer to our client as a member of the animal kingdom and declare her to be untruthful, is highly defamatory of our client’s good character and unblemished reputation,” Ms Giles wrote.
“The cavalier manner in which those words were spoken make it plain that they were not spoken privately or in confidence.
“You are also aware that this distasteful character assassination of our client has been republished widely causing her immense hurt and distress.”
Ms Higgins alleges she was raped by a male colleague in the ministerial office of Senator Reynolds in March 2019.
Senator Reynolds has faced scrutiny over her handling of the sexual assault complaint, including for holding a meeting about the alleged incident with Ms Higgins in the same room it allegedly occurred.
She has also been questioned over her decision not to notify Prime Minister Scott Morrison directly about the rape allegation.
In her statement, Senator Reynolds said she had "never questioned Ms Higgins' account of her alleged sexual assault and have always sought to respect her agency in this matter."
Finance Minister Simon Birmingham said Senator Reynolds should make an apology "to the satisfaction of Ms Higgins", when asked if she should deliver this publicly.
In a statement on Thursday, Ms Higgins described the comments as "incredibly hurtful".
"I appreciate that it has been a stressful time but that sort of behaviour and language is never excusable," she said in a statement.
"It's just further evidence of the toxic workplace culture that occurs behind closed doors in Parliament House."
Mr Morrison has also described Senator Reynolds' remarks as “offensive", saying he did not condone them.
