Crown fight mushroom killer's 'inadequate' sentence

Prosecutors will argue triple murderer Erin Patterson's sentence was manifestly inadequate and it was inappropriate for the trial judge to fix a non-parole period.

Patterson, 51, is serving a life sentence after she killed her three lunch guests by serving them beef Wellingtons laced with death cap mushrooms in July 2023.

But it is her 33-year non-parole period that will be the focus of argument as her appeal hearing continues on Thursday.

Victoria's top prosecutor Brendan Kissane KC is expected to argue the trial judge should have jailed Patterson for life without parole and any other sentence was manifestly inadequate.

It comes after Patterson separately argued her murder convictions should be quashed because she suffered a substantial miscarriage of justice during her high-profile trial.

In the Victorian Court of Appeal on Wednesday, her barristers argued the decision to sequester the jury in the same hotel as the lead investigator was "catastrophic" to the case.

Barrister Richard Edney accepted there was no evidence the jurors had communicated with the parties but maintained it was a "fundamental irregularity" that should lead to a retrial.

Patterson was also "forced" to give evidence in her trial after the judge did not allow mushroom photos found her SD card into evidence, her lawyers argued.

Patterson's right to silence was compromised as a result, it was claimed.

The prosecution will make submissions on Thursday in response to Patterson's appeal grounds before turning to its own appeal.

Mr Kissane has already argued the jury sequestration issue was not a "catastrophic failure" and instead the evidence showed the jurors did not have contact with any other person.

The jury deliberated for seven days before finding Patterson deliberately served death cap mushroom-laced meals to her former in-laws Don and Gail Patterson, 70, and Gail's sister Heather Wilkinson, 66.

The three guests died after lunch at Patterson's Leongatha home, in regional Victoria, while Heather's husband Ian fell seriously ill from the meal but survived.

Mr Wilkinson and other members of the Wilkinson and Patterson families were in court on Wednesday for the appeal, alongside members of the public and dozens of journalists.