An Australian woman has been jailed for life, with no chance of release for at least 33 years, for murdering three relatives and trying to kill another with a toxic mushroom meal.

The jail term, one of the longest ever handed to a female offender in Australia, means Erin Patterson, 50, will be in her 80s before she can apply for parole.

A Supreme Court judge said Patterson's crimes were the "worst category" for offending and involved an "elaborate cover-up".

Patterson killed her in-laws Don and Gail Patterson, both 70, and Gail's sister Heather Wilkinson, 66, after serving them a toxic beef Wellington at her home in Victoria in 2023.

Heather's husband Ian Wilkinson, a local pastor, survived the lunch after recovering from a coma and has ongoing health issues related to the poisoning.