The admissions came under cross-examination in the Supreme Court on Tuesday, as she sues the state of Victoria for damages.
Ms Gobbo claims police acted negligently after officers groomed her to become a human source in late 2005, but the state is fighting the allegations in a judge-alone civil trial.
Tony Mokbel didn't threaten her with physical harm but abused and harassed her, Nicola Gobbo said. (Julian Smith/AAP PHOTOS)
Ms Gobbo first met with two members of the Source Development Unit on September 16, 2005, at an undisclosed Melbourne hotel.
Under questioning from the state's barrister Bernard Quinn KC, she agreed the officers did not threaten or force her to remain at the meeting.
But Ms Gobbo said she believed she had to stay.
"I am in a room with two senior police," she told the court.
"I guess it's a feeling - what I felt then was an expectation to do what they asked."
Earlier in her evidence, Ms Gobbo said she approached police after drug kingpin Tony Mokbel pressured her to get bail for an associate, known under the pseudonym Mr Bickley.
While Mokbel did not threaten her with physical harm, Ms Gobbo claimed he abused and harassed her "to get (Mr Bickley) out and make sure he did not say one word".
She said she felt trapped and afraid of what Mokbel might do if she did not comply.
"He was a very loud, difficult man," Ms Gobbo told the court.
Mokbel's extensive pressure was the final straw so she went to police for help and was then registered as a police informer in October 2005.
Tony Mokbel "was a very loud, difficult man." (Julian Smith/AAP PHOTOS)
Ms Gobbo conceded there were other people she could have gone to instead of the police, including the Victorian Bar's ethics committee, senior lawyers and others mentors.
She also agreed she could have stepped away from her role as a barrister after suffering a serious stroke in July 2004.
"I should have left and found another career completely," she told the court.
Ms Gobbo instead returned to her full workload after a few months, including taking on clients like Mokbel and his associates.
She was drawn to the high-profile cases.
Nicola Gobbo said she should have quit being a lawyer after suffering a stroke. (HANDOUT/ABC NEWS)
"That is probably one factor," Ms Gobbo said in evidence.
"As you can appreciate, it's a topic that has been a subject of some counselling sessions with my psychologist in years gone by."
Ms Gobbo said she understood in 2005 that it was risky to become an informer and some criminals had been killed for giving information to police.
On Monday, she told the court she was an "idiot" for becoming an informer but she believed it was the only solution.
"It was like I was given a lifeline - do this, help us and we'll fix the problem," Ms Gobbo said.
The 51-year-old's image is being hidden from public view in the trial, with only Justice Melinda Richards and lawyers able to see her as she gives evidence.
The trial continues.