Evil mushroom killer Erin Patterson has begun her last-ditch effort to walk free from a Melbourne jail.

Supreme Court of Victoria Justice Christopher Beale sentenced Patterson to life in prison on September 8, but set a non-parole period of 33 years.

On Wednesday, the now 51-year-old appeared in the Supreme Court of Appeal from the Dame Phyllis Frost Centre via video link, avoiding another uncomfortable face-to-face with her victims and their friends and families.

Justices Stephen McLeish, Lesley Taylor and Peter Kidd will determine Patterson's future after listening to all the evidence over the coming days.

Patterson, who appeared in court wearing an oversized jumper, messy long brown hair and glasses, was found guilty of the murders of Don and Gail Patterson, and Gail's sister, Heather Wilkinson.

They died after consuming death cap mushrooms served in Beef Wellingtons during lunch at her Leongatha home on July 29, 2023.

Pastor Ian Wilkinson survived the lunch after being critically ill, with Patterson also convicted of his attempted murder.

Patterson had reportedly been expected to be represented by barrister Julian McMahon - a Companion of the Order of Australia and a Senior Counsel who counts the heroin smuggling ringleaders of the Bali Nine among his highest-profile defendants.

Instead, barrister Richard Edney appeared for Patterson, instantly launching into submissions calling for his client to be released from jail.

'I'll start with ground one, and your honours will see that that ground is expressed that a fundamental irregularity occurred while the jury were sequestered, that has fatally undermined the integrity of the verdicts and requires the quashing of the convictions and an order for a retrial so that justice can not only be done but be seen to be done,' he said.

Such is the public interest in the hearing, it needed to be moved from the actual appeal court to the larger Supreme Court of Victoria next door.

In opening his submissions, Mr Edney claimed the jury's placement in a hotel alongside journalists, police and prosecutors was unfair.

'We would describe the sequestration and what occurred during it as catastrophic, and in our submission, what has occurred here is that there has been a fundamental failure to comply with the dictum already referred to,' he said.

The court heard that despite Mr Edney's complaints, there was no evidence the jury had come into contact with anyone involved in the trial.

'This was a hotel with windows, with common areas and the reasonable possibility cannot be excluded that the jurors sighted the informant or sighted solicitors from the Office of Public Prosecutions.'

It was a submission instantly questioned by the judges: 'If they did view or see the practitioners, so what?' Justice Peter Kidd pondered.

Patterson's other barrister Veronika Drago then addressed the judges about concerns centred around the prosecution's use of evidence about the website iNaturalist and mobile phone tower data.

The prosecution had alleged that Patterson used iNaturalist to track down death cap mushrooms. 

Ms Drago argued that phone tower evidence and evidence about death cap mushroom sightings in the nearby towns of Loch and Outtrim caused unfair prejudice and should not have been permitted in the trial.

Ms Drago claimed the prosecution framed 'innocuous' evidence to turn nothing into something.

She further attacked the expert evidence of Dr Matthew Sorell, who provided hours of evidence on mobile tower records. 

Ms Drago submitted call-charge records were unreliable, and that the prosecution used Dr Sorell's subjective opinion and tried to present it as objective evidence.

'The question has to be asked how such speculative evidence ... how could it go to a fact in issue?' she said.

Moving to Patterson's third ground of appeal, Ms Drago claimed that the use of photos of foraged mushrooms ought not have been put to the jury. 

The court heard Patterson's defence had wanted to use the same evidence to prove Patterson always had an interest in foraging mushrooms, but was denied before the trial.

'By the time that very same evidence is sought to be relied upon ... by defence, the prosecution objected on the basis of the evidence being irrelevant,' Ms Drago said.

Ms Drago claimed there had been a substantial miscarriage of justice as it forced Patterson to testify that she had been foraging for mushrooms before.

'That she was compelled at all ... arises to the level of a substantial miscarriage of justice,' she said. 

'The truth is that in our submission she was compelled, and that amounts to or offends one of the cardinal principles or fundamentals of criminal law that is an accused's right to silence.'

Back on his feet, Mr Edney complained that Patterson was unfairly cross-examined by Crown prosecutor Dr Nanette Rogers. 

The barrister argued that the prosecutor's repetitive questioning - specifically asking the applicant if other witnesses were 'wrong, incorrect, or mistaken' - diverted the jury from their proper task. 

'What this repeated questioning about whether other witnesses were wrong, mistaken, or incorrect was that the jury might have had or formed the impression that the applicant had to provide a reason as to why those witnesses were saying the things that they were were saying,' he said. 

As the hearing continued, the court heard Patterson's defence barrister at trial, Colin Mandy SC, did not pursue Mr Edney's various complaints when provided the opportunity at the time. 

The court heard the defence had made at least 35 complaints about the prosecutor's final address, but Mr Mandy only raised a handful in his closing address. 

'The defence counsel was very alive to the complaints that you're now making under ground six. So alive was he to them that he raised most of them in his final address,' Justice Taylor said. 

'When one looks at the final address delivered by a very experienced trial counsel, the complaints that you are now raising, they were on the table at the time. 

'Nothing was being overlooked here, and rather than pursue other remedies, such as the prosecutor's address has led to a mistrial, a forensic decision was made to capitalise on these issues in order to maximise the applicant's prospects of an acquittal. So nothing's been overlooked here. 

'And what can be inferred from that is that defence counsel not only made a forensic decision, but did not perceive at that stage that the trial was irrevocably unfair.'

Patterson's attempt to overturn her conviction carries its own risks to her liberty.

Top Melbourne criminal lawyer George Balot, of Balot Reilly Criminal Lawyers, told Daily Mail she could face even further time behind bars if unsuccessful.

'So if she puts in an appeal against conviction and she's successful ... and a retrial is ordered, some of the evidence will be played on video for a new jury,' he said when the appeal was launched.

'So not all the witnesses will have to go through the same process. In addition to that, evidence that might have been excluded in previous trials might not be excluded on this trial.

'So it's very important to keep that in mind and, you know, be careful as to what you wish for.'

Patterson had been fortunate in having crucial police evidence withheld from the jury, which will likely be re-introduced should a retrial be ordered.

'And another interesting thing ... is if she succeeds on her conviction appeal, she might then be able to go back to the Supreme Court, plead guilty and receive a discount for a plea of guilty and saving the community a trial,' Mr Balot said.

'And so she could potentially do better than 33 years if she takes advantage of that.'

As Patterson fights to clear her name, Victorian prosecutors have lodged their own legal challenge, and are calling on the Court of Appeal to strip her of the chance to ever walk free again.

After Patterson was found guilty, the prosecution called on Justice Beale to impose a life sentence with no parole, a measure that would effectively see her locked up until she dies.

Justice Beale ordered the life sentence but set a non-parole period, giving Patterson a chance to walk free in 2056, when she would be aged 81.

The Office of Public Prosecutions believes Justice Beale's sentence was 'manifestly inadequate' given the gravity of Patterson's crimes.

Patterson had been brought to justice by Det Leading Sen Const Stephen Eppingstall, who was in charge of the investigation against her.

The respected detective had been grilled during Patterson's original trial, but was instrumental in convincing the jury that Patterson had indeed done what he had alleged. 

When the appeal is finally settled over the coming days or weeks, the full extent of the detective's case against Patterson is expected to finally be revealed.  

The hearing continues.