Erin Patterson's conviction for the deaths by poisoning of her estranged husband's relatives has prompted fevered speculation across Australia about her motive.

The Supreme Court has revealed the jury was accidentally sequestered in the same hotel as a key police witness and two members of the prosecution's team for the majority of the deliberations.

The jury in the Supreme Court trial in Victoria state returned a verdict after six days of deliberations, following a nine-week trial that gripped Australia.