Bruce Lehrmann, the man accused of raping Brittany Higgins in Parliament House, has started legal action against two media companies in the federal court.

Lawyers for Lehrmann, a former Coalition staffer, sent legal letters to media companies about possible defamation action in December, but the exact nature of the case filed on Tuesday was unclear.

Lehrmann is suing Network Ten and News Life Media, the publisher of news.com.au and part of the Rupert Murdoch media empire, federal court registry records show.

He filed a statement of claim, originating application, and genuine steps statement in the Ten cases at 3.18pm on Tuesday, the registry shows, with the second case filed about 20 minutes later.

No further information regarding the legal case was available. A spokesperson for Lehrmann was contacted for comment.

Lehrmann was alleged to have raped Higgins in 2019, which he denies. His trial collapsed in October after a juror brought in outside research papers on sexual assault. Prosecutors then abandoned the re-trial in December, citing concerns about Higgins’ mental health.

He has engaged Mark O’Brien, who has previously worked for Ben Roberts-Smith in his defamation case against Fairfax.

Last week, the ACT government announced that an independent inquiry into the handling of the case would be completed by Walter Sofronoff KC, an eminent retired Queensland judge.

The inquiry was prompted after explosive allegations about police conduct made by the director of public prosecutions, Shane Drumgold. The allegations were detailed in a letter to the police chief, Neil Gaughan, obtained by the Guardian through freedom of information laws.