The National Party has appealed a ruling that it breached copyright by using Eminem's track Lose Yourself for a 2014 election ad.
The High Court last month awarded Eight Mile Style, the publisher of the hit song, damages, plus interest from June 28, 2014 – a total of about $600,000.
National has now filed an appeal with the Court of Appeal.
In its earlier ruling, the High Court ruled that would be the "hypothetical licence fee" that would have reasonably been charged for permission to use Lose Yourself in National Party advertising.
The court noted Eight Mile Style had exclusive control of the song's licensing, and rarely granted permission for the song to be used in ads.