Actor Craig McLachlan has filed defamation proceedings against the ABC and Fairfax Media, which reported on allegations he sexually harassed several former colleagues.

Victoria Police is currently investigating allegations McLachlan committed multiple sexual offences while performing in the Rocky Horror Show in 2014.

A joint ABC/Fairfax investigation revealed three women from the 2014 production claimed McLachlan took advantage of his raunchy role as Dr Frank-N-Furter to indecently assault, intimidate and harass them, both on and off stage.

McLachlan has denied the allegations, describing them as baseless.

The Gold-Logie-winning actor has engaged barrister Stuart Littlemore QC and lodged a statement of claim in the New South Wales Supreme Court.

The action came after the producers of the Doctor Blake Mysteries cleared McLachlan of separate claims that he sexually harassed his co-workers, but admitted the show's workplace culture was "bawdy and crude" and may have offended some cast and crew members.

Two weeks ago, production company December Media hired a workplace consultant, Fiona Bigelli, to investigate claims of sexual misconduct on the set of the top-rating TV show.

Sorry, this video has expired Craig McLachlan, from Neighbours to Doctor Blake.

December Media said in a statement that Ms Bigelli had interviewed a "sufficiently large number" of people who worked on Season 5 of the production, and had produced a confidential report.

"But there were no findings of sexual harassment, sexual misconduct or workplace bullying by Craig McLachlan or any other person on Doctor Blake," the statement said.

"People highlighted the fact that Doctor Blake's workplace culture has consisted of, amongst other things, a workplace humour which has been described by many as sexual, lewd, bawdy, 'Benny-Hill-esque' and crude and that some of the behaviour relating to this humour may be offensive to people, regardless of the fact no formal complaints have been received.

"While December Media has all appropriate policies and procedures in place with respect to workplace behaviour, the report does recommend some improvements to be in line with world-best practice.

"We intend to implement these improved practices and share them with the rest of our industry".