Australian prosecutors said Monday they had launched an appeal against last month's "manifestly inadequate" sentence for convicted murderer Erin Patterson, local media reported, after a trial that drew global attention.

Patterson, 51, was handed life in prison with parole last month for serving a sumptuous beef Wellington laced with poisonous fungi to her estranged husband's parents, aunt and uncle during a lunch at her home in 2023, killing three of them.

But local media, including national broadcaster ABC and the Sydney Morning Herald, quoted Victoria State's Office of Public Prosecutions as saying it had appealed that sentence.

"We confirm that a DPP appeal has been filed on the basis that the sentence handed down to Erin Patterson is manifestly inadequate," the office said.

The Victoria Office of Public Prosecutions did not respond to a request for confirmation from AFP.

Last week, Patterson's lawyer Richard Edney told an administrative hearing at Victoria's Supreme Court his client also intended to "appeal against conviction".

He did not outline the reasons for the appeal.

In September, Patterson was sentenced to life in prison but a judge said she would be eligible for parole after 33 years.

Her legal team had argued she should be given the chance of release after 30 years because the notoriety of her case would have meant she would spend most of her prison sentence in isolation.

Prosecutors said however that Patterson should be jailed for life without parole because her offence was of the "worst category".

Throughout a trial lasting more than two months, Patterson maintained the beef-and-pastry dish was accidentally poisoned with death cap mushrooms -- the world's most lethal fungus.

But a 12-person jury found Patterson guilty in July of murdering her husband Simon's parents, Don and Gail Patterson, as well as his aunt Heather Wilkinson, at her home in Leongatha, in the state of Victoria.

She was also found guilty of attempting to murder Ian, Heather's husband.