The music publishers for American rapper Eminem filed a lawsuit Tuesday against New Zealand’s ruling political party over the music it used in a campaign commercial. The disputed ad depicts a boat filled with people rowing together, aimed at symbolizing the party’s unity. A spokesman for the two companies, Detroit-based Eight Mile Style and Martin Affiliated, said the two publishers previously sued Apple for using an Eminem song in an ad without permission and have been in a dispute with Audi over alleged infringing use of “Lose Yourself.” The National Party said in a statement that it would vigorously defend the action. It said the music it used was originally published by Spider Cues Music in Los Angeles and sold to it by an Australian-based supplier.