A writ lodged in the West Australian Supreme Court on Monday says Mr Drumgold sent a letter accusing the senator of "disturbing conduct" during Bruce Lehrmann's rape trial.
The letter to the Australian Federal Police was widely reported by media allegedly causing Senator Reynolds significant "loss and damage", according to the document seen by AAP on Thursday.
The Guardian broke the story in late 2022, with an article headlined "Bruce Lehrmann trial: ACT's top prosecutor complained about Linda Reynold's disturbing conduct".
It published parts of the letter to ACT Chief Police Officer Neil Gaughan following a freedom of information request after Lehrmann's trial was abandoned.
Mr Drumgold alleged Senator Reynolds had "engaged in direct coaching of the defence cross-examination of the complainant".
The senator is claiming aggravated damages with interest and an injunction restraining Mr Drumgold and the ACT government from republishing the material.
She is also suing former political staffer Brittany Higgins and her partner David Sharaz over a series of social media posts that she says have damaged her reputation.
Ms Higgins alleged she was raped in 2019 by Lehrmann inside the ministerial office of Senator Reynolds, where he also worked as a staffer.
The senator has accused Ms Higgins of posting defamatory material on two occasions on her Instagram and Twitter accounts.
Mr Sharaz is being sued over tweets he made and a Facebook comment in 2022.
Among the defamatory imputations claimed against Mr Sharaz's tweets were that Senator Reynolds pressured Ms Higgins not to proceed with a genuine complaint to police, "is a hypocrite in her advocacy for women's interests and empowerment", interfered in Lehrmann's trial and bullied Ms Higgins.
Senator Reynolds claims she was also defamed by Mr Sharaz's reply to a comment on her Facebook page that asked how she was still in politics having "destroyed" Ms Higgins.
The commenter added: "You're a monster who deserves to be in jail".
Mr Sharaz responded: "Thanks for reminding her. I hope she hears this every day until she dies".
Lehrmann consistently denied Ms Higgins' rape allegation, and his trial in the ACT Supreme Court was derailed by juror misconduct.
Prosecutors decided not to pursue further action, citing concerns of the impact it may have on Ms Higgins' mental health.
Lehrmann is suing Network Ten and journalist Lisa Wilkinson for defamation over a February 2021 report on The Project regarding Ms Higgins' allegation.
11°C