The publisher of United States' rap star Eminem is taking the National Party to court, with a hearing set down for next week.
Last year it was revealed that Eight Mile Style LLC and Martin Affiliated LLC, the Detroit-based publishers of Eminem's copyrights, intended to sue the The National Party.
They allege the National Party breached copyright by using a song that sounded similar to Eminem's 'Lose Yourself' in its campaign advertisements throughout the 2014 election.
Eight Mile Style will be taking a civil case against the New Zealand National Party, with a hearing scheduled for next Friday at the High Court in Wellington.
Eminem's publishers claimed they were not approached for permission to use any of Eminem's songs for the campaign advertisement.
"The National Party is defending this action and will not be making any further public comment until it is resolved."
In its earlier statement, the party rejected allegations the library music used in its campaign advertisements was a copyright infringement of any artist's work.
The party had purchased the music from production music supplier Beatbox, based in Australia and Singapore, the statement said.
"As with all works licensed by the Beatbox library music service, the National Party was assured the music in question did not infringe any copyright and was an original work," last year's statement read.
The music license and fee were arranged through the Australasian Performing Rights Association and Australasian Mechanical Copyright Owners Society (APRA/AMCOS), who act as agents for Beatbox in Australia and New Zealand, organisations which existed to protect the rights of artists, the party said.
"The National Party will be defending this action vigorously. As the matter is now before the courts we will not be making any further public comment."
National's campaign director Steven Joyce said he would not comment beyond the statement made by the party last year.
"The party and I stand behind the position on the 16th of September," he said.
Asked whether he stood by his comment at the time that the use of the music was "pretty legal", he said: "I'm not going to offer any further opinion at this point. I'm sure you've got a tape of what I said at the time."
Gus Hazel, a partner at James and Wells in Auckland, said if found liable the National Party was likely to have to pay a licensing fee and legal costs incurred by publisher, Eight Mile Style.
"In this sort of case, the likely licensing fees could have been significant, if the video featuring the music was to have been played widely and frequently; legal costs may run to tens of thousands by the time the case progresses very far."
Mr Hazel said it was not unrealistic to expect overall liability to be in the five-figure bracket.
Although a first hearing was set down for next week, it was unlikely the case would go to trial, as it was typical for parties to settle before that point, Mr Hazel said.
Regardless of whether or not the National Party purchased the music through what they considered a "reputable supplier" such as Beatbox, Eight Mile Style was within its rights to sue as the party had used the song in their campaign advertisement, Mr Hazel said.
"The reason they will be going after the National Party is because they are the ones that actually used the work."
However, Mr Hazel said if the National Party was found liable it could go after Beatbox with a claim to help pay any remedies, depending on the details of their contract with Beatbox.