Taxpayers face fresh costs after the FBI conceded it could take years to extradite Kim Dotcom on charges of criminal copyright violation.
The FBI has also taken a swipe at the New Zealand judge hearing the extradition case for making statements which cast doubt onthe strength of the case against Dotcom.
Dotcom was arrested with three Megaupload colleagues in January after a request for help from the United States.
The FBI accused Dotcom and others working at the company of the world's biggest case of criminal copyright violation.
The four charged here - and one other in the Netherlands - face trial in the US over allegations they oversaw a "Mega-conspiracy" of copyright violation. Two others are still wanted by the US authorities.
The raids brought down the Megaupload websites, which had previously carried about 4 per cent of the world's internet traffic.
Chief High Court Judge Helen Winkelmann yesterday issued a judgment which ordered the FBI to prepare copies of its evidence against Dotcom ahead of the August 6 extradition hearing.
It followed a sweeping order from District Court judge David Harveyfor the FBI to come up with its evidence.
Judge Harvey, who will hear the extradition case, told the FBI it had 21 days to provide Dotcom's lawyers with evidence held here and in the US relevant to this stage of the case.
The ruling left the US complaining Judge Harvey had ordered the release of too much information and it would take too long and be too hard to copy.
Justice Winkelmann ordered the US to start work on preparing the evidence, but said there would be an urgent two-day judicial review hearing into Judge Harvey's decision.
Justice Winkelmann said it was possible the extradition hearing could be delayed but the FBI had to do all it could to try and meet the August 6 date.
She overruled objections to cost as "the expense involved in copying must be dwarfed by the other costs" involved in investigating and prosecuting the case.
She said the FBI should continue pulling information together while preparing for the judicial review hearing, noting "the longer the United States takes ... the longer it will take".
The FBI had objected to having to copy the information, saying the data held in New Zealand would take two and a half months to copy, pushing out the date for the extradition hearing.
The bureau said there were 10 million emails and large amounts of financial data.
The claims set the scene for two pivotal hearings - the New Zealand judicial review and a June 29 hearing in the US.
Papers filed ahead of the US hearing say Judge Harvey was wrong when he said FBI charges had used civil law concepts in a criminal copyright case.
The defence has argued that there was no criminal law governing website owners when copyright violation was carried out by others.
The FBI said Judge Harvey had given weight to claims by Dotcom's defence which had no basis in evidence.
US Attorney Neil MacBride said Dotcom's lawyers had made an "attempt to exaggerate the complexity of the criminal charges".
Mr MacBride said Dotcom and the co-accused had infringed copyright and encouraged others to do so.
The papers also show the FBI attempting to head off an attempt by Dotcom's lawyers to have charges against his Hong Kong-based file sharing company dismissed - a move which would unlock an $80 million legal fighting fund.
Dotcom's lawyers, who were granted permission to appear for one of the US hearings, told the court the Megaupload company had never been served and charges should be tossed out.
They claimed there was no ability under law for companies based outside the US to be served on criminal charges.By David Fisher @@DFisherJourno Email David