Erin Patterson, the woman at the centre of a mushroom lunch that resulted in the deaths of three people, has been charged with multiple counts of murder and attempted murder.

The 49-year-old has spent hours being questioned by homicide detectives after police arrested and drove her from her Leongatha home in the state's Gippsland region to Wonthaggi police station.

She has this evening been charged with three counts of murder and five counts of attempted murder.

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The murder charges and two of the attempted murder charges relate to the mushroom lunch earlier this year, while the remaining three attempted murder charges relate to historical incidents.

"The murder charges and two attempted murder charges relate to an incident on 29 July where four people were taken to hospital after they fell ill following a meal at a private residence in Leongatha," a statement from police reads.

"The further three attempted murder charges relate to three separate incidents in Victoria between 2021-2022.

"It's alleged a 48-year-old Korumburra man became ill following meals on these dates."

Patterson has strenuously denied any wrongdoing previously.

Earlier today Detective Inspector Dean Thomas said the arrest was the "next step" in what has been a long investigation.

"While we do want to provide timely updates about this matter, it is critical that doing this does not adversely impact the current investigation or any future processes," he said.

"I encourage people to be particularly mindful of unnecessary speculation and the sharing of misinformation."

A search warrant was executed at Patterson's Gibson Street address today with the help of technology detector dogs from the Australian Federal Police (AFP).

Patterson was previously questioned and released without charge by detectives from the Homicide Squad in August.

Thomas said over the last three months the investigation has been subject to "incredibly intense levels" of public scrutiny and curiosity.

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"I cannot think of another investigation that has generated this level of media and public interest, not only here in Victoria but nationally and internationally," he said.

"I think it's particularly important that we keep in mind that at the heart of this, three people have lost their lives. 

"These are three people, who by all accounts were much beloved in their communities, are greatly missed by their loved ones.

"These deaths also continue to have a significant impact on the immediate families of those involved and I ask that people are particularly mindful of this over the coming days.

"In smaller communities, such as Leongatha and Korumburra, a tragedy such as this can reverberate for years to come."

On July 30 four people were hospitalised after they shared a meal at Patterson's Leongatha home the day prior.

Heather Wilkinson, 66, her sister Gail Paterson, 70, and her husband Don, also aged 70, died in hospital after the incident.

A fourth man, Reverend Ian Wilkinson, was recently released from hospital after weeks of extensive treatment.

All four had shared a meal, understood to be a beef Wellington, allegedly cooked by Patterson.

Investigators were exploring if the four had consumed death cap mushrooms, a rare but poisonous mushroom that is thought to be responsible for 90 per cent of mushroom-related deaths globally.