The extent of Melbourne criminal barrister turned snitch Nicola Gobbo's police informing has made it "impossible" for a royal commission to produce a report by the end of this year.
The Victorian inquiry into police use of informers has been granted another $20.5 million and an extension to carry out public hearings.
Led by commissioner Margaret McMurdo, it's the recruitment and management of people used to supply information to police including the gangland barrister who represented some of the state's most notorious underworld criminals.
When the inquiry was announced it was understood Ms Gobbo had been registered as Informer 3838 from 2005 and 2009, but was still providing information until 2010.
But it was revealed in January she'd first been recruited in 1995 and again in 1999.
"The increased span of inquiry into Ms Gobbo's activities, coupled with a multitude of suppression orders and numerous other information delays has made reporting on our first term of reference by 1 July 2019 impossible," Ms McMurdo said on Saturday.
The first task is focused on the number and extent to which cases might have been affected by police use of Ms Gobbo as a source.
Her former clients include gangland killer Carl Williams and drug lord Tony Mokbel, who is already seeking to appeal a 30-year sentence on the basis of her informing.
The inquiry is also considering the conduct of police who recruited, handed and managed her as an informer.
An interim report due for release on July 1 this year will be replaced with a progress report to be presented to the state governor.
A final report has been pushed back from December to July 2020.
The Victoria Court of Appeal, which is also seeking similar information in relation to Mokbel's appeal has sought its own progress report from lawyers on June 30.
They're also handling appeal applications by drug trafficker Rob Karam, who is serving a 35 year sentence, and Zlate Cvetanovski, who is due to be released after serving a more than decade-long sentence next year.
Attorney-General Jill Hennessy said the extension and further funding request had come from the commission.
"The complexities of dealing with a large volume of sensitive material that requires timely and detailed analysis, as well as security of the evidence, has resulted in the need for additional funding," Ms Hennessy said.
Former detective Paul Dale, who handled Ms Gobbo before being charged with murdering her former client and fellow police informer Terence Hodson and his wife Christine, will give evidence when hearings resume on June 17.
Charges against Mr Dale were later dropped.
Australian Associated Press