Patterson's appeal period was due to expire at 11.59pm on Monday, but her new barrister Richard Edney today applied in the Victorian Supreme Court for an extension.
Justice Christopher Beale granted the application, noting the court's new practice note where appeal extensions are automatically granted if only an additional 28 days are sought.
While the paperwork is yet to be filed, Mr Edney indicated to the court that Patterson would be lodging an appeal against her murder and attempted murder convictions.
The Director of Public Prosecutions is yet to decide whether it will appeal Patterson's sentence, a spokeswoman confirmed.
Patterson was jailed for life in September with a non-parole period of 33 years after she was found guilty of killing her former in-laws Don and Gail Patterson, 70, and Gail's sister Heather Wilkinson, 66.
The jury found she deliberately served beef Wellingtons laced with death cap mushrooms to her lunch guests in July 2023.
Heather's husband Ian Wilkinson also ate the meal and fell seriously ill, but survived.
Patterson, who this week celebrated her 51st birthday in custody, has always maintained her innocence and claimed it was a terrible accident.
Barrister Colin Mandy, SC, represented Patterson during her triple-murder trial but Mr Edney will be the one to lead the fight to quash her convictions in the Victorian Court of Appeal.
He previously represented Rebecca Payne, who was convicted of murdering her abusive husband by feeding him drug-laced biscuits and locking him in a freezer.
Payne was originally jailed for 16 years but successfully reduced her sentence on appeal down to 12 years.
