She also advised at least three of them to give evidence against the drug kingpin and other gangland figures.

Officer Green said he had some logistical concerns but he didn't believe there were any legal issues with enlisting Ms Gobbo as an informant.  

"As it was transpiring at the time, I didn't think we were doing anything wrong," he told the court on Tuesday.

The officer understood the anti-gangland Purana Taskforce was targeting Mokbel's associates to "roll" against the drug kingpin so they could end the "mayhem" of the gangland war.

Ms Gobbo began advising three of her clients, known in court as Mr Thomas, Mr Cooper and Mr Bickley, to turn against Mokbel.

Officer Green told the Supreme Court he didn't fully appreciate she was abusing her legal privilege by advising her clients to roll. 

"The way I see it, she's representing her client and she's trying to get the best deal for him," he said.

Officer Green said it started to dawn on him that Ms Gobbo was too close to the situation, but mostly because of the risk to her safety rather than for ethical reasons. 

"I would be worried about her coming into harm - she told us that Tony would kill her," he told the court. 

Mokbel, 58, is trying to appeal drug trafficking and incitement to import charges he was sentenced for in 2012. 

His original 30-year prison term was cut to 26 years with a non-parole period of 20 years following a Court of Appeal decision in 2023. 

Mokbel is now challenging the overall convictions, arguing Ms Gobbo tainted his case.

But before a substantive appeal hearing can start, Justice Elizabeth Fullerton needs to rule on several legal questions. 

The justice has been brought in from NSW to oversee the determination hearings, which are expected to run for 12 weeks.