Details of the top secret international spy agency ring known as Echelon will have to be produced after a new judgment in the Kim Dotcom case.

The internet tycoon was also cleared to pursue a case for damages against the police and the Government Communications Security Bureau in a judgment which has opened the Government's handling of the criminal copyright case for its harshest criticism yet.

The order for the GCSB to reveal top secret details came as the High Court at Auckland ruled the spy agency would now sit alongside the police in a case probing the unlawful search warrant used in the raid on Dotcom's north Auckland mansion.