Mushroom killer Erin Patterson's appeal against triple murder conviction set for August

Mushroom killer Erin Patterson will return to court in August to appeal her triple murder conviction, Victoria's Supreme Court has confirmed.

Patterson was convicted and jailed for life in September with a non-parole period of 33 years for the murder of her parents-in-law, Gail and Don Patterson, and Gail's sister, Heather Wilkinson.

She was also convicted of the attempted murder of Heather's husband, Ian Wilkinson, 69, who fell seriously ill after eating the meal but survived.

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The 51-year-old's appeal hearing will be heard on August 19 and 20.

The Director of Public Prosecutions (DPP) will front court on those dates to appeal the length of Patterson's non-parole period, which it claimed is "manifestly inadequate".

Patterson's lawyers lodged a formal application to appeal her convictions in the Supreme Court in November.

Patterson claimed there was a "fundamental irregularity" while the jury was sequestered during the trial.

After the jury was sent out for deliberations, it was revealed they had been placed in the same hotel as the police informant and two members of the prosecution team.

Patterson further claimed a "substantial miscarriage of justice occurred" because of the prosecution's "unfair and oppressive" cross-examination of her when she gave evidence over several days in the trial.

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She said the prosecution's opening and closing arguments also caused a substantial miscarriage of justice because they introduced an implied motive at the end of the trial.

The mushroom cook has also taken issue with evidence that was aired in court.

Justice Christopher Beale noted in sentencing Patterson that her offending was the worst category of murder and represented a betrayal of trust towards people she considered family.

But he showed Patterson mercy with the chance of parole, noting she was essentially in solitary confinement for at least 22 hours a day.

Acting Director of Public Prosecutions Diana Piekusis KC said the judge had erred by finding there was a "substantial chance" Patterson would be held in solitary confinement for years to come.

Her sentence of life in prison with a non-parole period of 33 years will make her Victoria's longest-serving female prisoner.

– with AAP