The Court of Appeal has upheld a decision that allows Kim Dotcom to sue the Government's spy agency.
The internet entrepreneur, a German national with New Zealand residency, is seeking compensation from the Government Communications Security Bureau (GCSB) and police for illegal surveillance and a raid on his home near Auckland in January 2012.
The Attorney-General tried to keep the GCSB out of the proceedings by appealing against a High Court ruling that allowed Mr Dotcom to combine his claims for compensation from police and the agency.
But in a decision released on Thursday the Court of Appeal rejected the challenge, saying it is not appropriate to intervene in the High Court's proceedings.
When the case resumes at the Auckland High Court on 15 April, the Government's spies may be grilled about their involvement in the case and why they were illegally spying on Mr Dotcom and his three co-accused.
Mr Dotcom's lawyers earlier won the right to view the spy agency's evidence against their client, but Thursday's ruling overturned that, saying there is no basis for the agency to make disclosure.
However, the Court of Appeal has limited how much of the material gathered by the GCSB has to be revealed to those involved. It urged the parties to co-operate to make sure that the case is determined as quickly as possible.
A lawyer for Kim Dotcom said they would seek compensation from the spy agency, but have not yet put a figure on how much they intend to sue for.
Willie Akel told Radio New Zealand's Checkpoint programme on Thursday they hope to cross-examine people from the GCSB about the whole operation when the case is heard at the High Court.
Mr Akel said they have not been able to see evidence collected by the spy agency.