Fatal Australian mushroom lunch suspect Erin Patterson arrested

The woman who prepared a mushroom lunch that killed three people in Australia has been arrested, according to local media reports.

Erin Patterson was arrested on Thursday morning, The Age reported citing a source "with knowledge to the case". However, charges have not been laid.

Patterson's home is currently being searched by the Australian Federal Police with detector dogs, 7 News said. In the meantime, she was being questioned at Victoria's Wonthaggi police station.

Don and Gail Patterson, Erin's former parents-in-law, and Heather Wilkinson became sick and later died after attending a lunch cooked by Erin in the rural Victoria town of Leongatha in late July.

A fourth man, Wilkinson's husband Ian, was hospitalised in a critical condition. He was released from the hospital in September.

Erin has previously denied any wrongdoing.

"I am… devastated to think that these mushrooms may have contributed to the illness suffered by my loved ones. I really want to repeat that I had absolutely no reason to hurt these people whom I loved," she said in a statement obtained by local media earlier this year.

Erin's initial account to the police was she bought the mushrooms served at the lunch from a local shop, 7 News reported.

However, at the time, no warnings or recalls were issued on produce in the area.

Detective Inspector Dean Thomas from the Victoria homicide squad provided an update on the case on Thursday.

"This morning detectives arrested a 49-year-old female in relation to this incident, and a search warrant was subsequently executed at her residential address," Det Insp Thomas said.

"Homicide squad investigators have previously interviewed this woman in relation to an incident that occurred on 29 July where four people fell ill.

"Three people have lost their lives. These are three people who by all accounts were much beloved in their communities and are greatly missed by their loved ones."

Det Insp Thomas said although the arrest is "the next step" in a "complex and thorough investigation", it is "not yet over".

He said once the search is complete, Patterson will be interviewed by homicide squad investigators.