Eminem's legal team are heading to the Supreme Court, as the copyright stoush over the National Party's 2014 election advertisement drags on.

Photo: Jeremy Deputat

In 2017, the High Court found the music library track "Eminem-esque," which backed one of the party's election campaign videos, substantially copied the rapper's song 'Lose Yourself'.

The court ordered the National Party to pay $600,000 to Eight Mile Style, Eminem's music publisher, for the breach of copyright.

National went to the Court of Appeal to challenge that and in a judgment in December, the court quashed the original damages award and ordered the party to pay $225,000 instead.

Eight Mile Style is now going to the Supreme Court to challenge that judgment.

Documents were filed last month and the court is now awaiting submissions.