Erin Patterson, the Australian woman jailed for life after being convicted of murdering three relatives with poisonous mushrooms, will return to court this week in a bid to overturn her convictions.

Patterson, 51, was found guilty last year of murdering her estranged husband’s parents, Don and Gail Patterson, both 70, and Gail’s sister, Heather Wilkinson, 66.

She was also convicted of attempting to murder Heather’s husband, Ian Wilkinson, who survived after becoming gravely ill.

The case, which transfixed Australia and generated a flood of podcasts, books and television programmes, centres on a family lunch at Patterson’s home in Leongatha, in Victoria’s Gippsland region, on 16 July 2023.

The meal was beef Wellington prepared with death cap mushrooms.

Patterson has always denied deliberately poisoning her relatives.

She maintained during her trial that the inclusion of the highly toxic mushrooms was an accident and that she panicked and attempted to conceal what had happened afterwards.

A two-day hearing at the Victorian Court of Appeal in Melbourne will begin on Wednesday.

It is an application for leave to appeal – the formal stage at which Patterson must persuade the court that her case should proceed to a full appeal.

The prosecution and defence will present written and oral arguments before a panel of three judges decides whether there are grounds for an appeal.

If successful, Patterson could have her convictions quashed, with the court potentially ordering a retrial or acquitting her. If the application fails, her convictions will remain in place.

She could then seek to take the matter to Australia’s highest court, the High Court.

Patterson is not expected to attend the hearing in person and is instead likely to appear by video link from prison.

In documents filed with the court last year, she claimed she had suffered a “miscarriage of justice” during the 11-week trial and set out seven grounds of appeal.

She argued that the prosecution’s five-day cross-examination of her was “unfair and oppressive” and that its closing address “caused a substantial miscarriage of justice”.

Her lawyers also claimed the prosecution had “changed its case” by suggesting a motive for the killings during its closing arguments, despite prosecutors saying in their opening statement that there was no known motive.

Patterson further challenged evidence involving mobile phone cell towers and sightings of death cap mushrooms around Loch and Outtrim in Victoria, both of which had been used by prosecutors at trial.

Her final ground of appeal concerns what she describes as a “fundamental irregularity” involving the jury’s sequestration during deliberations.

The Victorian Supreme Court previously confirmed that the 12 jurors had unknowingly been staying at the same hotel as the lead detective and two members of the prosecution team.

The appeal hearing comes as prosecutors themselves challenge Patterson’s sentence.

She was sentenced in September 2025 to life imprisonment with a non-parole period of 33 years for the three murders, with a concurrent 25-year sentence for the attempted murder of Mr Wilkinson. If the prosecution succeeds in its appeal, she could instead receive a life sentence without the possibility of parole or a non-parole period longer than 33 years.

Patterson will be 82 when she becomes eligible to seek parole in 2056 under her current sentence.

The non-parole period of 33 years was the longest ever imposed on a woman convicted of murder in Victoria.

Patterson’s lawyers had argued for parole eligibility after 30 years, while prosecutors had called for her to remain behind bars for life.

The deaths devastated the close-knit rural community of Korumburra, where the victims lived.

The case also placed Patterson under extraordinary public scrutiny. Her estranged husband, Simon, told the sentencing hearing that the media attention surrounding the case had been traumatic for the family.

Australia abolished the death penalty, meaning a life sentence is the maximum punishment available. Only one woman – Katherine Knight – in the country has previously received a life sentence without the possibility of parole for the murder of her partner, John Charles Thomas Price, in February 2000.