Internet entrepreneur Kim Dotcom has won the right to have New Zealand's highest court decide whether his lawyers will be given FBI documents relating to the extradition case against him.
The Court of Appeal had ruled that United States prosecutors did not have to hand over evidence they are relying on in the case.
The US wants to extradite Kim Dotcom, a German national with New Zealand residency, and three other people to face charges including internet piracy, racketeering and wire fraud relating to his internet file-sharing business MegaUpload. The site has been shut down.
In May 2012, the District Court ruled that Mr Dotcom should be able to see the evidence in his extradition case, and that was upheld by the High Court.
The Court of Appeal then ruled that the US only had to provide a summary of the evidence against Mr Dotcom relating to his extradition proceedings.
Mr Dotcom's lawyers then decided to take the fight to obtain documents from the US for his extradition hearing to the Supreme Court.
In a ruling released on Thursday, the Supreme Court has allowed an appeal against the Court of Appeal's decision.