German police have raided stands at CeBIT, the world's largest computer exhibition.

Over 180 officers raided 51 stands as the exhibition was preparing to close, claiming that they were checking out allegations of copyright infringement.

Associated Press reported that 24 of the stands were operated by companies from mainland China, three from Hong Kong, 12 from Taiwan, nine from Germany, and one each from Poland, The Netherlands and Korea.

Hanover police claimed that the "number of criminal complaints by the holders of patent rights in the run-up to CeBIT has been rising for years".

Police took away 68 boxes with gadgets and documents, according to a police statement, ranging from phones and monitors to GPS mapping systems and digital picture frames.

The patent infringements are alleged to include devices with MP3, MP4 or digital video broadcast functions, as well as DVD players and blank CDs and DVDs, police said.