An Australian woman, accused of killing her in-laws with a toxic mushroom-laced beef Wellington, pleaded not guilty to a raft of murder charges on Tuesday, court officials said.

Erin Patterson faces three counts of murder for allegedly dishing up a poisonous meal in July 2023 that killed her parents-in-law, as well as the wife of a local pastor.

The 49-year-old, who is also accused of attempting to kill her estranged husband four times, indicated to a Melbourne court that she would fight the charges.

Court officials said the case, which has captured headlines around the world, would now be fast-tracked for trial at the Supreme Court of Victoria.

Patterson allegedly served the beef Wellington to her estranged parents-in-law Don and Gail Patterson, both 70, as well as local Baptist pastor Ian Wilkinson, 69, and his wife Heather Wilkinson, 66.

Police have previously suggested the meal she served included lethal death cap mushrooms.

Three of the lunch guests -- Don and Gail Patterson, and Heather Wilkinson -- died in the days following the meal.

Ian Wilkinson recovered after spending nearly two months in hospital.

Detectives said husband Simon Patterson also "became ill after meals" served by his estranged wife on four separate occasions in 2021 and 2022 -- and have charged Erin Patterson with his attempted murder. (AFP)