Mushroom murderer Erin Patterson is being kept in near constant isolation, leaving her frightened and supporters fear at risk of psychological decline.
A prisoner rights group is advocating on the triple murderer's behalf for her to receive peer counselling to improve her mental wellbeing at no cost to the state.
Patterson's conditions at Dame Phyllis Frost Centre, west of Melbourne, involve being confined to a cell for a minimum of 22 hours a day and having approved contact with just one other prisoner through a wire mesh during limited yard time.
Advocacy group Justice Action has called the treatment tantamount to torture, invoking United Nations rules named after Nelson Mandela, which say a person shouldn't spend more that 15 consecutive days in solitary confinement.
The group is yet to be allowed direct contact with Patterson, but says information from other prisoners in the same unit suggests she is in a poor mental state.
Justice Action co-ordinator Brett Collins, who is a former inmate, said Patterson was entitled to be treated like any other prisoner and to serve her time constructively.
"She's a frightened woman, understandably so," he told AAP on Friday.
"She's actually been now isolated for such a long time, and she's already had those disorders before she before she was convicted, so now we've heard she's unused to people being around her.
"That's the sort of behaviour that causes causes permanent damages. It's torture, actually."
Justice Action is proposing Patterson be permitted a trained peer support mentor to help address and mitigate the psychiatric risks, which it would offer at no cost to taxpayers.
The now 51-year-old was convicted of murdering three former extended relatives by serving them beef Wellingtons laced with death cap mushrooms at a lunch in July 2023.
In sentencing Patterson, Justice Christopher Beale made her eligible for parole after serving 33 years behind bars, citing in part the extended period she was expected to spend in solitary confinement due the risks she faced from other prisoners.
Mr Collins said Patterson's chosen method of murder could make her particularly unpopular with other female prisoners.
"What they're arguing is that other prisoners are hating her because of what she did," he said.
"There's like a women's expectation as well, that the family that ate with her trusted her and that there was a breach of that trust."
A spokesperson for the Department of Justice and Community Safety said while it does not comment on individual prisoners or their placements, all prisoners had regular contact with prison staff, health professionals, lawyers and chaplains.
