The lone surviving guest of a lunch where three others died after being served food laced with deadly mushrooms told an Australian court on Monday the actions of host and convicted murderer Erin Patterson had left him feeling "half alive".

Australian toxic mushroom killer Erin Patterson faces her victims' relatives in court Monday before a judge sentences her for a triple murder that made headlines worldwide.Patterson now faces a two-day pre-sentencing hearing at the Supreme Court of Victoria in Melbourne as the judge ponders her punishment.

The sole survivor of a deadly lunch laced with toxic mushrooms said on Monday he felt only half alive following the death of his wife and he continued to grieve the loss of his two closest friends.