The National Party has gone to the Court of Appeal in a bid to decrease the amount of damages it has to pay for breaching copyright in its 2014 election campaign.
Last year the High Court found the music library track "Eminem-esque," which backed the Nats' election campaign videos, substantially copied the rapper Eminem's song "Lose Yourself".
Justice Cull ordered the National Party to pay $600,000 to Eight Mile Style, Eminem's music publisher for the breach of copyright.
However the party's lawyer, Greg Arthur, today questioned how that figure was reached.
He told the Court of Appeal today National would only have needed to pay for an 11-day licence to use the music and while the party preferred the "Eminem-esque" track, there were alternatives available.
"It could have chosen other production music which would have cost around $5000 or it could [have] commission[ed] music which would have been about $20,000."
The actual amounts involved in the case were suppressed by the High Court as they were commercially sensitive and they have not been referred to in the Court of Appeal.
Mr Arthur said one of the women who gave evidence at the trial about the amounts involved in music licensing deals referred to figures that were a significant percentage higher than any New Zealand deals, but admitted she had no knowledge of the local licensing landscape.
He said Justice Cull's decision was also influenced by evidence from Joel Martin about what the fee should be, but that should not have been given any weight as he was a manager of Eight Mile Style.
Mr Arthur said Justice Cull found there was 'intensive use' of the "Eminem-Esque" track during the 11 days the National Party election campaign ad aired.
"But there was no evidence about what was the usual 'intensiveness' of use.
"It was about 3 times a day per channel - I don't have evidence on whether that was intensive or not."
Mr Arthur said it appeared the judge made no allowance for anything that was favourable to the National Party.