The crossbench senator threatened with legal action after telling a colleague "to stop shagging men" has received advice any defamation case is his to win.
Liberal Democrat senator David Leyonhjelm made the remark about Greens senator Sarah Hanson-Young amid a parliamentary debate on legislation seeking to prevent violence against women.
He then doubled down on his remarks in live interviews on Sky News and Melbourne radio station 3AW, where he made further "appalling" comments about her private life.
Senator Hanson-Young tweeted on Monday night to say she's taking legal action on behalf of all women who have "had enough".
"The legal advice I've received would suggest she's not likely to win," Senator Leyonhjelm told AAP on Tuesday.
"There's substantial risk to her. If she loses, she'll pay my costs - and the costs in a defamation action are not insignificant."
Senator Leyonhjelm received a concerns notice a week ago that gave him seven days to respond, but says full legal action is yet to commence.
Following a prolonged public spat over his remarks, Senator Leyonhjelm has repeatedly refused to apologise.
GoFundMe campaigns have been created by supporters of both parties to contribute to their anticipated legal costs.
"I've had thousands and thousands of offers of support and people indicating that they're on my side," Senator Leyonhjelm said.
On Monday night, Senator Hanson-Young tweeted thanks to the creators of her GoFundMe campaign, saying any winnings would go to women's charities.
"I'm taking this action on principle, for all women who have had enough," she tweeted.
"Since calling out the sexist attack on me last week I've been flooded with stories from women ... This legal fight is for them."