Former crossbench senator David Leyonhjelm has appealed against a court finding that he defamed Greens senator Sarah Hanson-Young by calling her a misandrist and hypocrite.

In November, federal court judge Richard White ordered Leyonhjelm to pay Hanson-Young $120,000 after ruling that the former Liberal Democrat senator defamed Hanson-Young during media interviews in the middle of 2018.

Leyonhjelm made a series of appearances on radio and TV following a stoush in parliament during which he said Hanson-Young should “stop shagging men”.

He claimed that he said this in response to an interjection from Hanson-Young to the effect that “all men are rapists”, but, after hearing evidence from senators who were present at the time White found she did not do so.

Leyonhjelm resigned from parliament in January to pursue a spot in the NSW Upper House during state elections. He failed to win a seat.

He was represented by Queensland firm Sterling Law during the defamation trial but has hired a new lawyer, Brisbane-based Mark Stone, to mount the appeal.

Stone boasts on his website that he has “never lost a jury trial”.

There are no juries in federal court defamation proceedings.

In appeal documents filed with the federal court on Monday, Stone claimed White made a series of errors and said Leyonhjelm’s statements about Hanson-Young should also be protected by the implied right to freedom to discuss political matters contained in the constitution.

“Qualified privilege should protect public statements made by a politician regarding the conduct and character of another politician, which are not actuated by malice, without a further requirement of reasonable care in publishing the statement,” he said.

Leyonhjelm’s appeal relies on a 1997 case in which the high court found the constitution implied a right to freedom of political speech after New Zealand prime minister David Lange sued the ABC for defamation over a Four Corners program about donations from big business to his Labour party.

The high court decision narrowed the scope of the right from what had been established in a previous case involving Labor politician Andrew Theophanus, but upheld its existence.

In his appeal documents, Stone said White was wrong to find that Leyonhjelm “acted unreasonably by failing to verify with the respondent [Hanson-Young] or other senators whether she had interjected using words to the effect of those attributed her”.

He also argued that White’s finding that Leyonhjelm was motivated by malice should be set aside because “the motive of causing political damage to the respondent [Hanson-Young] or her political party could not be regarded as improper”.

And he said White was “wrong to have relied on authorities regarding the conduct of newspapers or broadcasters reliant on sources, but ought to have given primacy to the situation in which the appellant [Leyonhjelm] was a politician, discussing the conduct of another politician, in an incident in which he was himself a politician, and having heard the interjection himself”.

Hanson-Young told Guardian Australia that “while we haven’t considered the grounds of appeal yet, I expect my lawyers will vigorously oppose the appeal,” she said.

Stone and Leyonhjelm could not be reached for comment.