Now, her defence counsel Rupert Glover has indicated she will take her case to the Supreme Court.
In Court of Appeal correspondence with APNZ issued today, Justice Ellen France said Mr Glover "confirms an application for leave to appeal will be made to the Supreme Court".
A spokeswoman for the Supreme Court today said it had not yet received an application.
Mr Glover said he had applied for leave to appeal with the Supreme Court and was waiting to hear whether that was granted.
"[Milner] still maintains her innocence," Mr Glover said.
"And for that reason, she wants to appeal if there are any grounds to do so. I've looked at the situation and concluded that she may have grounds [to appeal]."
Milner argued in the Court of Appeal that the jury's verdict was unreasonable because the prosecution did not prove beyond reasonable doubt that it was possible for her to have administered the drug Phenergan without her husband noticing its bitter taste.
The Court found it was not necessary for the prosecution to prove exactly how the mother of two had administered the drug so Mr Nisbet did not know about it.
The mechanics of administering the drug was simply one factor for the jury to weigh up in the context of a strong circumstantial case, they ruled.
They added that other, circumstantial evidence supported the jury's verdict.
Purchases of Phenergan under fake names were linked to Milner, and her son Adam Kearns gave evidence that he had seen her crushing pills.
She had expressed a wish to kill Mr Nisbet and take advantage of his $250,000 life insurance policy.
And suicide notes given to the police by Milner contained errors and other features that matched samples of her writing.