Eminem's music publisher has filed a fresh multi-million dollar lawsuit against Apple, reports The Detroit News.

Filed Monday in the US District Court in Detroit, the lawsuit alleges that Apple is violating copyright by selling Eminem's music through iTunes.

But the litigation may amount to a conflict with the rapper's label, Universal, rather than Apple.

Eminem's music publisher and copyright manager, Eight Mile Style and Martin Affiliated, claim Apple isn't permitted to sell music by the artist because Eminem has not agreed to grant his label, Universal, the rights to sell such music.

Apple's deal is with Universal Music. Under that deal the company pays Universal a substantial slice of the money earned through iTunes sales.

However, Apple has been asked to stop selling Eminem's tracks and has so far refused, the report explains.

Music industry observers believe more such litigation will emerge in future, as artists and composers fight to take a bigger slice of the money earned by music downloads.

One unresolved matter is that of whether a record label also has the rights to authorize music downloads or whether such rights belong to music publishers.

Eminem's management previously sued Apple in 2004 over the use of Eminem song Lose Yourself in an iTunes TV ad. The ad was never actually aired.