Law firm Robinson Gill filed a statement of claim in the County Court of Victoria in May on behalf of Lesley Gilmour alleging Nine journalist Kate McGrath interfered with police attempts to peacefully end the siege, leading to the death of her son Antonio Loguancio???.

Loguancio, 40, shot himself on March 3, 2013, inside a Glenroy bungalow after a 43-hour siege with police.

Before and during the siege Loguancio made several calls to Ms McGrath, Channel Nine's chief of staff, including one that ran 54 minutes.

Ms Gilmour alleges this prevented police from negotiating his safe exit from the bungalow.

Police told a coronial inquest they explicitly asked Ms McGrath to stop speaking to Loguancio as she was getting in the way of negotiators - an allegation she denies.

The coroner's report into the death was scathing of Ms McGrath's conduct, but found she did not cause Loguancio's death.

"I never got the chance to get him out of the siege because of Channel Nine," Ms Gilmour told Fairfax.

"I never got the chance to say goodbye. I really think Channel Nine had a lot to do with it."

When he died, Loguancio had only been out of jail for less than a year after serving a 12-year sentence for the rape of his former partner. In February 2013 police issued a warrant for his arrest after he allegedly assaulted his then-partner, but Loguancio refused to hand himself in and instead holed up in a Glenroy bungalow with two firearms.

Police surrounded the bungalow and for 43 hours tried to get him to come out. He fired shots at them and threatened to turn the weapons on himself.

At the same time Loguancio called Ms McGrath to complain about misleading media coverage, in particular about reports he went by the nickname "Mad Dog". Ms Gilmour said his nickname was actually "the Mad Wog".

The lawsuit alleges Ms McGrath then called Loguancio back and they spoke for about 54 minutes. At least one of the phone calls was filmed in the office by a Channel Nine cameraman.

???Ms McGrath contacted police after her phone call, informing them that Loguancio was threatening suicide. Police say they advised her that they should be the only ones talking to him, and that she was interfering with a police operation - a claim Ms McGrath disputes.

"I didn't deviate from the message, which was 'Look, if you walk out with your hands up it's the best possible outcome for you and for your family'," she told the Coroners Court.

Coroner Audrey Jamieson's findings, handed down in March, were scathing of Ms McGrath - but said she did not cause his death.

"It ultimately amounted to an opportunistic exploitation of a significant police incident, executed by Ms McGrath without any consideration for the fact that she may be compromising police endeavours to have Tony surrender himself," she wrote.

"I find that Nine Network's direct communications with Tony during the siege were inappropriate and disruptive to the police operation but was not of itself, causative to the outcome."

Jeremy King, principal at Robinson Gill lawyers, said he would be arguing Ms McGrath's actions "heavily influenced the outcome of the siege".

"Police members were highly critical of her involvement in this case and the disruptive impact it had on the ability to peacefully resolve the siege."

A spokeswoman for Channel Nine said: "We are sorry for Ms Gilmour's loss, however, we reject the version of events alleged by the plaintiff and note the Coroner's finding that any conduct of Nine was not causative to the outcome."