The Court of Appeal has reserved its decision over questions raised about DNA evidence used to convict a man of murdering a German tourist.
Michael Scott Wallace was jailed for life with a non-parole period of 18 years for the murder of Birgit Brauer near New Plymouth in 2005.
His lawyer told the court an expert had found material on the metal bar, said to be the murder weapon, from a person unrelated to Ms Brauer or Wallace, and it was in the interests of justice for that to go to a jury.
However, the Crown said that was a debating point between experts and not something the Court of Appeal should use to rule the evidence was unsafe.
The Crown said the DNA evidence supported other circumstantial evidence relating to Wallace.