Kim Dotcom has lost the latest round of his extradition battle with US authorities.
A court has ruled the US does not have to hand over the source documents it relies on in its extradition case against Megaupload founder Dotcom.
The Court of Appeal has overturned a High Court decision that ordered the disclosure of the documents that are the basis of the case against Dotcom.
The court said extradition hearings were not trials and the full range of protections and procedures for criminal trials did not apply to extradition.
The US government can summarise its case in a streamlined procedure. The judge deciding whether to order extradition has to be satisfied that there is a case to answer.
If the court wants more information it should, in most cases, ask the Justice Minister to request it from the overseas authorities who want the person extradited.
The extradition hearing has not yet started. Justice Minister Judith Collins refused to comment while the legal process was ongoing.
Dotcom tweeted after the court's decision: "The fight goes on. Next is the Supreme Court of New Zealand."
Dotcom, 39, was arrested in a massive police raid on his rented Coatesville mansion, north of Auckland on January 20 last year.
Computers and assets were seized as New Zealand police co-operated with US authorities who want to extradite the German-born internet entrepreneur to stand trial on criminal charges alleging copyright piracy and racketeering.
Initially Dotcom was judged a flight risk and he was remanded in custody for about a month.
The Court of Appeal decision today is the latest in a series dealing with the legality of the January raid and whether Dotcom is entitled to have copies returned of the information seized in the raid.
In the course of the case it emerged that the Government Communications Security Bureau had been intercepting the communications of Dotcom and business associate Bram Van Der Kolk.
The surveillance was illegal because they have New Zealand residence and the bureau's powers are limited to collecting information about foreigners.
Dotcom's millions of dollars of assets are still frozen and he has to rely on the court ordering the release of money to him.
- The Dominion Post