Victoria Police has lost its latest bid to suppress the identity of Informer 3838, the lawyer whose role as a police informant at the height of Melbourne's gangland war sparked a royal commission.

Key points: Victoria Police has been battling to keep Informer 3838's identity suppressed

Victoria Police has been battling to keep Informer 3838's identity suppressed The Court of Appeal today dismissed Victoria Police's attempt to maintain the suppression on her identity

The Court of Appeal today dismissed Victoria Police's attempt to maintain the suppression on her identity Police and Informer 3838 have until next Friday to lodge appeals in the High Court

Victoria Police Chief Commissioner Graham Ashton and the lawyer at the centre of the legal scandal had applied to the Court of Appeal to prevent the former barrister's name being revealed.

However, the newly established Royal Commission into Management of Police Informants argued in court that the identity of the informant, also known as Lawyer X, should be revealed.

The Commonwealth Director of Public Prosecutions, along with the Victorian Office of Public Prosecutions, also fought against the application to suppress her identity.

It is the latest attempt by Victoria Police to stop the identity of the lawyer, already known in legal and criminal circles, from being made public.

Victoria Police spent at least $4.52 million on legal battles to keep the identity of Informer 3838 suppressed due to fears she and her family "would be murdered".

But the Court of Appeal today ruled that the latest applications from police and Informer 3838 herself to prevent her identity being made public should be dismissed.

The lifting of the suppression of Informer 3838's identity was stayed until next Friday to allow Victoria Police and Informer 3838 time to lodge a High Court appeal.

Due to today's hearing occurring in a closed court, the reasons for the dismissal of attempts to extend the suppression order were not published.

Convictions at risk

Informer 3838 represented some of Victoria's most serious gangland criminals including Carl Williams, drug kingpin Tony Mokbel and Mokbel's associate, drug trafficker Rob Karam.

Over several years she provided information to Victoria Police about her clients, in an arrangement previously described by the High Court as "reprehensible".

Tony Mokbel is currently serving a 30-year jail term for drug trafficking. ( AAP: Julian Smith )

The Office of Public Prosecutions last year wrote to 20 convicted criminals, including drug kingpin Tony Mokbel, to inform them of the lawyer's role as a police informer in their cases, believing that those people could move to have their convictions quashed.

The Court of Appeal ruled last year that the risks of prosecutors informing criminals of the informer's actions were outweighed by "the public interest in the right to a fair trial with the assistance of independent legal advice".

The revelations sparked a royal commission into the use of Informer 3838 and Victoria Police's management of police informants more broadly.

Its chair, Margaret McMurdo, said in her opening address that the commission's legal team had been "steadily addressing existing suppression and non-publication orders to ensure the commission has access to all relevant materials".