The only guest to survive a toxic mushroom lunch with Australian murderer Erin Patterson said on Monday he feels "half alive" without his wife, who was one of the three victims.

Pastor Ian Wilkinson wept in court as he spoke of the loss of his wife Heather after she ate a beef Wellington dish laced with death cap mushrooms – the world's deadliest fungi.

Patterson, 50, was convicted in July of serving the poisonous fare to her husband's parents, aunt and uncle at a sumptuous lunch in her rural home in the state of Victoria in 2023.

Within days, the parents and aunt were dead, but the uncle – Ian Wilkinson – survived after weeks in hospital to give testimony at his host's murder trial, which became a global media sensation.

Patterson was present in the Supreme Court of Victoria in Melbourne for the two-day hearing, set aside for relatives to testify to the impact of her crimes and for lawyers to argue over the severity of her sentencing.

"I continue to carry a heavy burden of grief over her untimely death. It is a truly horrible thought to live with that somebody could decide to take her life. I only feel half alive without her," the pastor said of his wife, Heather.

Wilkinson, who spent weeks in hospital after sharing the same beef-and-pastry meal, said his own health had never fully recovered.

"I very, very nearly died. It has taken me the best part of two years for my health and strength to recover to the point that they have," he said.

"I have reduced kidney function, ongoing respiratory issues and reduced energy. And I have had to face the many challenges of reestablishing life without Heather."

The home cook's husband, Simon Patterson, who had declined an invitation to the deadly lunch, told the court of his grief over the loss of his relatives.

"I miss my parents and aunt more than words can express. I will be aware for the next 30 years that they could still be alive had Erin chosen not to murder them," he said.

"My children, two children, are left without grandparents as a result of these murders. They have also been robbed of hope for the kind of relationship with their mother that every child naturally yearns for."

"The grim reality is they live in an irreparably broken home with only a solo parent, when almost everyone else knows their mother murdered their grandparents."

At the trial, a 12-person jury found Patterson guilty of murdering her husband Simon's parents, Don and Gail Patterson, as well as his aunt Heather Wilkinson, by serving them the meal at her home in Leongatha, Victoria, in July 2023. (AFP)