The Privy Council has been told it was a conscious and tactical move by the defence in the trial of convicted double murderer Mark Lundy to force the Crown to make its case around the timeframe when his wife and daughter were killed.
Lundy is serving a life sentence for killing his wife Christine Lundy, 38, and their seven-year-old daughter at the family's Palmerston North home in August 2000.
He was arrested six months later and jailed for 17 years after being found guilty of the murders. In 2002, the Court of Appeal threw out his case and increased his minimum non-parole period to 20 years.
The hearing in London was told on Wednesday that it had suited the defence to preserve the 15-minute timeframe.
The Crown's case at the trial was that Lundy drove from Petone in Lower Hutt to Palmerston North and back in three hours and committed the murders in that time.
Lundy's legal team has submitted that the time of death was established by examination of stomach content - a method it said was internationally discredited as bad science.
For the Crown, New Zealand Deputy Solicitor-General Cameron Mander said Lundy's lawyers had not presented fresh evidence. He said the defence had been aware of conflicting views of experts at the time of the trial but chose not to use them.
Four members of the judicial committee of the Privy Council and New Zealand's Chief Justice Dame Sian Elias are hearing the appeal, which ended on Wednesday. It is expected to be several weeks before they make a decision.
Following the hearing, Lundy's lawyer David Hislop, QC, said the ideal outcome would be for the Privy Council to order a retrial and for the Crown to decide it was not in the public interest to hold one, thus allowing his client to go free. His second most favoured outcome would be a retrial of ''a very strange case''.
Mark Lundy's brother-in-law, Dave Jones, said he was pleased with how the hearing went and there was a lot of information reviewed in just three days. He said he and his wife Caryl, Lundy's sister, would ideally like to see a retrial.
But Christine Lundy's brother believes Mark Lundy should lose the appeal. Glenn Weggery said his family and supporters believe believe police got the right man when he was convicted.
Mr Weggery said the worst scenario would be if the case goes back to the High Court for a retrial, forcing them to relive the trauma after spending the past 13 years trying to move on.