Greens senator Sarah Hanson-Young has sent a legal letter to David Leyonhjelm after he refused to apologise for his "appalling" comments about her private life.
The independent senator made offensive comments told his female counterpart in parliament last week, and on Sunday alluded further to her private life on a Sky News broadcast.
Senator Hanson-Young called on the Liberal Democrat senator to apologise and resign, but she's also taken legal advice from lawyer Rebekah Giles about a possible defamation action.
She said Ms Giles has sent letters to Senator Leyonhjelm and broadcasters Sky News and 3AW.
Malcolm Turnbull has also called for David Leyonhjelm to apologise for his offensive comments to Greens senator Sarah Hanson-Young, saying it's not too late to withdraw his remarks.
The NSW Liberal Democratic Party senator told his female counterpart to "stop shagging men" during a debate in federal parliament last week and on Sunday alluded further to her private life in an interview on Sky News.
The prime minister said he couldn't remember similar language in parliament.
Mr Turnbull said all violence against women stemmed from disrespect, stressing the need for respect in the workplace.
"It was clearly offensive, it should have been withdrawn and apologised for. It's not too late for him to do so now," Mr Turnbull told reporters in Sydney on Tuesday.
Senator Leyonhjelm said he was offended by her comments, but didn't know the exact wording.
"I am opposed to misandry as I am opposed to misogyny. I am entitled to call out double standards," he told the ABC on Monday.
Senator Leyonhjelm's comments drew condemnation from Foreign Minister Julie Bishop, Education Minister Simon Birmingham, former prime minister Tony Abbott, and multiple Sky News hosts including Andrew Bolt, David Speers and Peta Credlin.