One of the lawyers for Megaupload founder Kim Dotcom says New Zealand needs to stand up to US agencies.

Dotcom's lawyers are seeking a judicial review of the legality of the search warrants used by police who raided his mansion on behalf of the FBI.

The US Government is seeking to extradite Dotcom and three New Zealand-based associates on charges including copyright infringement and wire fraud relating to the file-sharing website Megaupload.

Prosecutors allege a "mega conspiracy''.


Dotcom denies the charges and says his website was legitimate.

US lawyer Ira Rothken told Radio New Zealand the case was turning into a "procedural battle, rather than one on merits".

"They're using tactics, rather than substance to try and win the case," Mr Rothken said.

"By going ahead and taking down all of Megaupload and not agreeing to preserve the servers - that to us is a red flag that they're concerned that if we get all the evidence we are going to prevail."

Mr Rothken said New Zealand need to stand up to overseas authorities, such as US Government agencies.

"Our concerns are that the United States will have New Zealand take all the data and all the hard drives that have been confiscated and remove them from the New Zealand jurisdiction, essentially making it so the New Zealand judiciary cannot exercise New Zealand's views, New Zealand's values in fairness and due process, and bring it all over to the United States so that it cannot be used in the extradition hearing."

Dotcom lawyer Paul Davison QC yesterday told the High Court at Auckland Dotcom wanted digital copies of his 135 computers and hard drives to help in the defence of his case and that was his right under common law and the Bill of Rights Act.

Justice Helen Winkelmann yesterday queried what the police were authorised to take under the search warrant.

"They were clearly entitled to search and seize evidence in relation to the copyright but that did not give them carte blanche to take everything.''