Ousted former Victorian Liberal MP Moira Deeming has given Opposition Leader John Pesutto seven more days to respond to a legal ultimatum or face defamation action in court.
A third letter of concern claims Mr Pesutto hasn't offered to resolve her complaint, which stems from the fallout following a women's group rally outside the Victorian Parliament in March attended by transgender activists and a far-right group.
Mr Pesutto's office declined to comment when approached on Saturday afternoon.
The legal letter alleges Mr Pesutto made "baseless and false" imputations about Ms Deeming at a press conference in March, including accusing her of being a Nazi sympathiser and associate.
Mr Pesutto has previously denied he accused the now independent MP of being a Nazi or having Nazi sympathies.
Ms Deeming was initially suspended from the Liberal party for nine months after taking part in the Let Women Speak rally, which was also attended by neo-Nazis who she says gatecrashed the event.
Ms Deeming was eventually expelled in May.
AAP has seen a copy of the third letter of concern sent by Ms Deeming's lawyers on July 14.
The letter claims Mr Pesutto has not offered to make amends since a first letter of concern was sent several months ago.
It includes an offer to resolve the dispute if he agrees to never repeat statements made about Ms Deeming and several other demands within a week.
The requests also include paying her legal costs, handing over compensation and signing a letter of apology to be displayed prominently on his website and social media platforms for 14 days.
The letter comes six weeks out from the upcoming by-election in the state seat of Warrandyte, triggered by the resignation of veteran Liberal MP Ryan Smith.
