A copyright payout owed to US rapper Eminem by a New Zealand political party has been slashed on appeal.
The conservative National Party was last year ordered to pay the Detroit musician's label, Eight Mile Style, $NZ600,000 ($A570,530) after using a track that bore striking similarities to the song Lose Yourself in a 2014 election campaign ad.
But in a verdict returned by New Zealand's Court of Appeal on Tuesday, judges cut the payment to $NZ225,000 after the party's lawyers questioned how the original sum had been reached.
"Given the evidence of the expert witnesses for both sides, it was not open to the High Court to adopt the baseline figure that it did," a court statement said.
"The advertising message was only relevant to a relatively small population."
Lose Yourself was composed by Marshall Mathers III (Eminem), Jeff Bass and Luis Resto - who formed the Eight Mile Style company - in 2002.
Bass played the recognisable opening riff to the 2002 song for the High Court court last year, saying it was the most valuable in the catalogue and had never been used in a political campaign.
National paid $NZ4800 for a song called "Eminem-esque" to a production company in 2014, with the tune appearing 186 times on television, as well as on the internet and at a party conference.
High Court Justice Helen Cull ruled that song was "substantially" copied and awarded the payment despite the party's arguments it had been told by industry professionals there would no legal issues with Eminem-esque's owners.
In October, a representative for Eminem said the rapper would donate any money awarded to hurricane relief efforts in the United States.
Australian Associated Press
