In September, the former federal opposition and NSW One Nation leader was ordered by the Federal Court to pay independent MP Alex Greenwich $140,000 in damages over the tweet sent during the 2023 state election.
The sexually explicit tweet was sent days after a heated online argument between the two politicians and called Mr Greenwich "disgusting".
The post came in response to a tweet by the independent NSW politician describing the then One Nation state head as a "disgusting human being".
In September, Justice David O'Callaghan found the tweet was defamatory and resulted in a loss of standing to Mr Greenwich who experienced a barrage of online ridicule that was entirely foreseeable.
Mr Latham was ordered to pay $140,000 in damages.
He has retained solicitor Zali Burrows - who has also represented disgraced ex-deputy mayor Salim Mehajer and former Liberal staffer Bruce Lehrmann - to appeal these findings, including the amount the court wants him to hand over.
In a notice of appeal seen by AAP, Mr Latham argued that Justice O'Callaghan was wrong to find the tweet was defamatory and contained an imputation that Mr Greenwich "engages in disgusting sexual activities".
The judge also allegedly erred by finding that the independent MP suffered serious harm as a result of the post.
Mr Latham is seeking to re-agitate defences that he posted the tweet as his fair opinion which was justified as a response to an earlier attack.
Mr Greenwich declined to comment on the pending appeal.
The graphic post was widely criticised by those across the political spectrum, including One Nation leader Pauline Hanson.
The online sparring match between the two politicians followed violent protests outside a church in Sydney's southwest where Mr Latham was giving a pre-election speech in March 2023.
About 250 mostly male counter-protesters violently attacked police and 15 LGBTQI protesters who had set themselves up outside the Belfield church.
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