Ozzy Osbourne is suing his Black Sabbath band mate Tony Iommi in a dispute over ownership of the group's name.

The rocker has filed a lawsuit in a federal court in Manhattan, New York, accusing guitarist Iommi of falsely proclaiming to be the sole owner of the Black Sabbath moniker after he filed documents with the U.S. Patent and Trademark Office.

Osbourne alleges he is largely responsible for catapulting the heavy metal stars to fame in the 1970s and that his "signature lead vocals" resulted in the band's "extraordinary success."

The singer also points out the dip in popularity of Black Sabbath between 1980 and 1996, when he was dropped from its line-up, as evidence of how instrumental he is to the band's legacy.

According to the New York Post, Osbourne is seeking a 50 per cent interest in the Black Sabbath trademark and a cut of the profits Iommi has garnered from the use of the name.

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