Australian Prime Minister Scott Morrison has said his defence minister "deeply regrets" making "offensive remarks" about an alleged rape victim.
Linda Reynolds has not denied a report that she referred to her former aide Brittany Higgins as a "lying cow".
Ms Higgins has alleged she was raped by one of Ms Reynolds' ex-advisers - a charge that has rocked the government.
When asked if Ms Reynolds should quit, the PM said her remark had come "in her private office in a stressful week".
Last month, the former political adviser alleged she had been attacked in Ms Reynolds' office at Parliament House after a night out in 2019. The man was later sacked for a separate reason.
The Australian newspaper reported Ms Reynolds had made her disparaging remark on the day Ms Higgins told her story to the media.
In a statement, Ms Reynolds said she had never questioned Ms Higgins' sexual assault allegation.
"I did however comment on news reports surrounding circumstances that I felt had been misrepresented," the defence minister said late on Wednesday.
Responding on Thursday, Ms Higgins said the remark was "incredibly hurtful" and such language was "never excusable".
"It's just further evidence of the toxic workplace culture that exists behind closed doors in Parliament House," she said.
On Thursday, Mr Morrison said he had spoken to Ms Reynolds and she had acknowledged the comments were "inappropriate and wrong".
Ms Higgins' decision to go public has prompted a wave of other allegations - including a rape accusation against Attorney General Christian Porter which he strongly denies.
Opposition lawmakers have heavily criticised Ms Reynolds - some had already called on her to resign over her handling of Ms Higgins' case.
"She's gone this morning. She needs to resign immediately," said independent Senator Jacqui Lambie on Thursday.
Independent MP Zali Steggall said: "It makes her position all the more untenable."
Ms Reynolds took a period of medical leave last Wednesday amid public pressure over the response by her office to Ms Higgins' allegation.
Last month in parliament she said she was "deeply sorry that some of my actions and handling of this matter added to Brittany's distress".
Ms Higgins has told local media she felt unsupported by her boss and pressure that she would lose her job if she reported her alleged rape to police.
In the fortnight since she went public, other women have come forward with allegations against the same man. Allegations against others have also been aired publicly.
In the most high-profile case, Mr Porter - a senior government minister - has been accused of raping a 16-year-old girl in 1988, when he was aged 17. Mr Porter has strongly rejected the allegation.
Police have been unable to pursue an investigation, citing the matter is closed due to "insufficient admissible evidence". The woman took her own life last year.
In Australia, an alleged victim's testimony is typically required - particularly in sexual assault cases - for police to proceed with an investigation that has chance of prosecution.
Mr Porter - who as attorney general is Australia's top legal officer - has said he will not stand down and retains Mr Morrison's support.