Kim Dotcom

Kim Dotcom's extradition has become less certain after a judgment which will see the FBI having to prove it has the evidence to back up its charges.

It also found the legal document asking he be sent for trial in the United States did not comply with the law.

The ruling came on a day in which Dotcom went back to the High Court at Auckland to again seek access to his restrained funds - this time to pay lawyers' bills which he has said are now worth millions of dollars.

The judgment followed moves by the Crown to have a judicial review into an order which forced an extensive release of evidence in the case. The order, by the District Court, ordered the FBI to produce some of the evidence it held against Dotcom so it could be tested during the extradition hearing.

It was challenged to the High Court, which has upheld the earlier finding.

The decision by chief High Court Justice Helen Winkelmann is the final decision in an argument over whether the extradition hearing would some of the substance of the FBI's claims to be probed. Crown Law had maintained it was a limited process while Dotcom has argued he should be allowed to challenge the FBI case.

The internet tycoon denies charges of criminal copyright violation, conspiracy and money-laundering in relation to his Megaupload filesharing website, which once carried 4 per cent of the world's internet traffic.

Justice Winkelmann said the role of the extradition court was "modest'' and the process could not take over the role of the trial court.

But she said it had the same character as a committal process which would see evidence in New Zealand criminal courts weighed before proceeding to a full trial.

As part of that process, it was open for the defence to present its own evidence, test the prosecution's claims and to examine witnesses, she said.

She also found the "Record of Case", the document which made the argument for extradition, did not currently meet the legal requirements.

She said the FBI was under an "obligation of candour'' to provide any evidence which could impact on the court's judgment of whether the extradition threshold had been met - and no information had been provided to support FBI claims. The document "did not comply", she said.

Justice Winkelmann said Dotcom had a legal right to see the evidence on which he was to be extradited.

Without it, she said someone in his position would be "significantly constrained'' in participating in the extradition hearing and the United States - in this case - would have a "significant advantage'' by having access to the evidence.

- By David Fisher of the New Zealand Herald