The legal team for convicted rapist and murderer Teina Pora is considering asking for his case to be heard by the Privy Council.
Pora was convicted in 1994 of the rape and murder of Susan Burdett and again after a retrial in 2000 but his legal team argues that the conviction was based on a false confession.
They have asked for a Royal Prerogative of Mercy in which the Governor-General can grant a pardon or ask for a case to be sent back to court.
But Pora's lawyer, Jonathan Krebs, says his team has now uncovered significant evidence that may carry enough weight to warrant an application to the Privy Council in Britain.
They would first have to seek the Court of Appeal's leave to appeal to the council.