Tanya Levin, 43, was banned by church management in 2005 from attending any Hillsong events or setting foot on Hillsong premises.

But she assumed she was on safe ground when a reporter from Channel Nine's A Current Affair invited her to be interviewed outside the Allphones Arena at Sydney Olympic Park while the megachurch's conference took place inside.

During the interview Ms Levin was approached by two police officers who told her she was trespassing and would be fined if she did not move on.

"I had thought Sydney Olympic Park was public property and that's why I agreed to go," Ms Levin said.

"I didn't think I was doing anything wrong. I have complied with Hillsong's request to stay away for the last ten years," she said.

Ms Levin moved to about 200 metres from the arena to an area she believed the officers had indicated and had a brief conversation with a young conferencegoer.

About 15 minutes later she was arrested for trespassing.

Ms Levin was escorted into the arena where she was interviewed by police and served with a banning notice for Sydney Olympic Park before being allowed to leave through the car park.

"They said I crossed the perimeter, but there was no fence or barrier or anything," she said.

The officers were not attached to any specific local area command, but were user-pay officers contracted to patrol the conference site.

Ms Levin wrote An Insider's Story Of A Life In & Out Of Hillsong after becoming disillusioned with the multinational pentecostal church in 2001 and began asking questions about the church's leadership and its ministry.

But Hillsong said Ms Levin's actions were "a cheap publicity stunt".

In a statement to Fairfax Media, Hillsong alleged A Current Affair and Ms Levin were "harassing minors in an unethical manner" outside the conference.

"The behaviour of A Current Affair is reprehensible and this pending story will be no more than a continuation of their anti-Christian agenda and hate," the statement read.

Ms Levin denied her presence was a stunt.

"I don't have a criminal record. I didn't want to get arrested, and have to go to court," she said.

"It's very stressful when I know that the people I speak to who have been very badly treated by Hillsong are very distressed that a critic of the church would be arrested," she said.

Hillsong banned Ms Levin in 2005 for causing "significant disruption" to its Colour Your World Women's conference, according to a letter sent to Ms Levin by the church's general manager George Aghajanian.

But Ms Levin said the only disruption she caused was to express her disgust at a fundraising tactic used by the church to a handful of delegates including a relative of Hillsong's leadership.