Schapelle Corby had trafficked drugs into Bali three times before her arrest, and "acted crazy" to get her sentence cut, her former Australian cellmate Renae Lawrence claims.
Lawrence, one of the Bali Nine drug couriers, was secretly videoed making the allegations that were broadcast on Network Ten yesterday.
She said Corby, who was released from Bali's Kerobokan jail on parole in February, was good at keeping her secrets, but "let one slip one night".
"She said that she knew the marijuana was in the boogie bag, but the person who was supposed to be at the airport at the same time didn't turn up," Lawrence said.
"She told me and the other prisoner that she'd done it more than this time.
"She said she'd brought the drugs [into Bali] before three times."
Lawrence also claimed Corby "acted crazy" to get her sentence cut.
In 2012, Indonesian President Susilo Bambang Yudhoyono reduced Corby's sentence by five years, citing compassionate grounds.
"She said it herself, she played crazy so that she would get more sympathy and more time off from the President of Indonesia," Lawrence said.
"She would put on more of an act when someone important came into the block, like the doctor or the jail boss."
Corby's parole is already under review after her sister Mercedes gave an interview to the Seven Network in which she continued to argue her sister's innocence.
Authorities assessing whether Corby should be punished are also taking into account her mental state, after witnessing her attempt at self-harm and assessing her as "unstable".
The head of corrections in Bali, Sunar Agus, said he wouldn't comment on whether the Lawrence interview was an added complication until he had seen it. But it appears Lawrence may also be in trouble, because prisoners are allowed to give interviews from prison only with the permission of the Justice Ministry.
Lawrence was moved from Kerobokan jail to another prison in Bali in October, amid accusations the 36-year-old had conspired with another inmate to murder two female guards.
But because of her good behaviour, she was again moved last month to a less-isolated jail.