The Crown is appealing a High Court ruling that search warrants used in the Kim Dotcom case were illegal.
Chief High Court Justice Winkelmann's ruled last month that search warrants used to raid Dotcom's Auckland mansion were invalid.
Dotcom, 37, ran the world's largest file-sharing site from his $30 million mansion in Auckland, before he was arrested in a dramatic raid on charges of money laundering, racketeering and copyright infringement.
Justice Winkelmann said the search warrants were invalid because they were general warrants which lacked specificity about the offence and the scope of the items to be searched for.
Without a valid warrant, police were trespassing and exceeded what they were lawfully authorised to do.
Justice Winkelmann said no one had addressed whether police conduct also amounted to unreasonable search and seizure, but her preliminary view was that it did.
Dotcom, 38, is on bail awaiting an extradition hearing.
United States authorities say he and his three co-accused - Mathias Ortmann, Fin Batato and Bram van der Kolk - used Megaupload and its affiliated sites to knowingly make money from pirated movies and games.
Dotcom is charged with multiple copyright offences.
- Fairfax Media
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