A glamorous gangland lawyer who has spent years trying to out a barrister who ratted on her clients to Victoria Police for $2.8 million has told A Current Affair we haven’t heard half the story yet.

Zarah Garde-Wilson is famed for her steamy GQ magazine shoots and her high-profile love-affair with convicted murderer Lewis Caine.

Caine ended up a victim of Melbourne’s bloody gangland war when he was gunned down in 2004.

Melbourne lawyer Zarah Garde-Wilson. (AAP)

But the gangland lawyer, portrayed in Nine’s television series Fat Tony , has proven she has a lot more to her than saucy shoots and dates with bad boys, playing a key role in exposing the questionable tactics employed by senior police as they sort to contain Melbourne gang war.

Victorian Premier Daniel Andrews yesterday announced a Royal Commission would investigate the use of an informant, known as ‘Lawyer X’.

“This is clearly just the tip of the iceberg,” Ms Garde-Wilson said.

“We first found out about this in 2014 as a fact (and then it) took us two years to get the information to file the proceedings. It wasn’t until 2016 when we had them filed and we’ve been waiting two years before the courts for this matter to come to a head.

“It pretty much undermines almost a decade of criminal cases.”

Ms Garde-Wilson said the Lawyer X affair undermined "almost a decade" of criminal cases. (A Current Affair)

Ms Garde-Wilson was romantically involved with murderer Lewis Caine, who was shot dead in 2004. (A Current Affair)

Ms Garde-Wilson told A Current Affair the Royal Commission would need to unpack hundreds of cases involving some of Australia’s most notorious crims.

“These cases all need to be scrutinised one by one,” she said.

“Every single one of them needs to be wound back to find what did actually go on, were they given a fair trial, and what are the consequences and results if they didn’t get a fair trial.”

The Melbourne gangland wars were at their height from 2007-11. (A Current Affair)

Melbourne gangland boss Tony Mokbel (AAP). (AAP)

Geelong Advertiser editor Liam Houlihan was a crime reporter at the Herald Sun at the height of gang war from 2007-2011 and has written books on the saga. He says some of the state’s worst criminals could be looking at freedom.

“If you’re his (Tony Mokbel’s) defence lawyer, you would say, how do we know that he was not convicted based on information given by the female barrister,” Mr Houlihan said.

“'How do we know that this isn’t tainted information that shouldn’t be covered by legal professional privilege.

Zarah Garde-Wilson says the Royal Commission into the use of an informant is "the tip of the iceberg". (A Current Affair)

“You would say that certainly gives rise to reasonable doubt.”