The first civil lawsuit has been filed against the website, Megaupload, and its founder, Kim Dotcom, in a United States court.
Mr Dotcom is on bail in Auckland while the US Government seeks to extradite him to face internet piracy and copyright charges in relation to his website.
His American lawyer Ira Rothken says two companies - Microhits and Valcom - have laid a single lawsuit claiming copyright infringements of the music recordings, films and television shows they own.
They are suing for an unspecified amount.
Mr Rothken says it looks like Microhits and Valcom are taking advantage of Mr Dotcom's current situation, as they have never given notice of an infringement before.