She's the most famous prisoner in Bali's corrupt and filthy Kerobokan Prison. Mentally unstable, protesting her innocence and drawing a constant stream of publicity to the drug infested jail, Schapelle Corby has already suffered retribution at the hands of guards and prisoners.

Now, with the publication of a sensational new book, which details a rampant drug culture, violent assaults and even murders, Schapelle's safety behind Kerobokan's walls is more fragile than it has ever been.

Bali Nine prisoner Renae Lawrence, who is close to Schapelle, voiced the fury of the Australians housed within Kerobokan, saying journalist Kathryn Bonella's book will do Schapelle serious harm.

"She's already under great mental strain, and this will make her more unpopular with the guards," says Renae who, as trustee and head of the women's block, has previously been appointed Schapelle's guardian to ensure she takes her medication on time every day.

"They don't like her because to them she's a troublemaker. And they could easily get back at her in different ways, making her life even more nightmarish."

Renae – who has been credited with saving Schapelle's life by coaxing her down from a prison water tower when she was threatening to jump – said it wasn't only the fact that Schapelle was being targeted putting her at threat.

"It's this kind of tension that's taking its toll on her mental state and could easily push her over the edge. I'm really worried for her. She's already said she would rather be dead. This is like a death sentence for her…"