David Leyonhjelm’s “stop shagging men” comment about the Greens senator Sarah Hanson-Young was much more likely to enhance her re-election prospects than harm her reputation, according to his defence to her defamation lawsuit.

The Liberal Democrats senator also contends that any reputation damage arose from her own words when she said “he’s slut-shaming me” during a radio interview.

Hanson-Young is suing Leyonhjelm over interviews he gave between 28 June and 2 July to Sky News, the Melbourne radio station 3AW and the ABC’s 7.30 program, and a media statement posted on medium.com on 28 June.

In the material, he elaborated on his admonishment to Hanson-Young on the floor of parliament to “stop shagging men” amid a debate on legislation seeking to prevent violence against women.

She says she was defamed by his portrayal of her as a hypocrite and misandrist, in that he says she claimed in parliament that all men are rapists but “nevertheless had sexual relations with them”.

A case management hearing took place in the federal court on Thursday, when Justice Richard White granted Leyonhjelm’s barrister, Tony Morris QC, an extension of time to file his defence.

His lawyers also filed an interlocutory application to have all or part of her case thrown out, on grounds including it containing “frivolous or vexatious material” and seeking to impeach or question “the freedom of speech and debates or proceedings in parliament”.

Hanson-Young’s barrister, Sue Chrysanthou, also pre-empted filing an updated statement of claim, saying Leyonhjelm’s “conduct” takes place on a daily basis and “I anticipate his conduct will continue”.

In the defence Leyonhjelm said Hanson-Young’s comment about him “slut-shaming” her were “calculated and intended to, and did achieve, a particular resonance amongst large parts of the Australian public”.

Her own words “substantially drowned out” the matters she was suing him about and were the cause of any damage to her reputation, the defence said.

She then engaged in “self-promotion”, making herself out to be “a champion of the rights of women”, which can only serve to enhance her public profile and “reinforce or enhance” her standing, reputation and esteem among her political supporters.

The defence maintained the Liberal Democrats and the Greens were widely understood to be “at polar extremes of the political spectrum in Australian politics”.

It logically followed that nothing said by Leyonhjelm would alter the opinions of a person who already held Hanson-Young in favourable esteem or took a neutral view towards her.

If his lawyers decide to pursue their interlocutory application, it will be heard on 18 October.