Labrador, the US supplier of the song at the centre of rapper Eminem's dispute with the New Zealand National Party, has been brought into the copyright infringement case.
Justice Robert Dobson rejected California-based Labrador's argument that it shouldn't be included in the case, claiming that its contract with the Australian supplier BeatBox meant any dispute should be fought in Californian Courts.
Eight Mile Style and Martin Affiliated, the Detroit-based publishers of the rapper's music, filed proceedings in the Wellington High Court last year, seeking damages for copyright infringement against the National Party.
The publishers claim the song used in an election campaign ad by the National Party is a rip off of Eminem's 'Lose Yourself' featured on the rapper's '8 Mile' movie.
Labrador owns the rights to the Eminem-esque song and has an extensive music library, which is used for productions. In 2009 it licensed BeatBox to use its musical library Spider Cues, which included the offending song.