The police investigation into the GCSB's spying on Kim Dotcom has been held up because the agency is involved in High Court proceedings over the raid on the internet tycoon's Auckland mansion.
The Green Party asked for the investigation, arguing the Government Communications Security Bureau breached the Crimes Act when it spied on Dotcom before he was arrested in January on allegations of internet piracy.
Police accepted the complaint but on December 7 Justice Helen Winkelmann ruled the GCSB could be added as a defendant in the ongoing judicial review of the lawfulness of the raid, when Dotcom was arrested on allegations of internet piracy.
The GCSB has admitted it acted illegally when it intercepted Dotcom's communications.
It didn't know at the time he was a New Zealand resident, and it is forbidden by law to spy on citizens or residents.
The police wrote to the Green Party on Wednesday saying Justice Winkelmann's ruling was "impacting on the technical processes" of its investigation and when those issues had been resolved an update would be provided in the new year.
Party co-leader Russel Norman says he understands the problems but thinks the investigation should reach a conclusion in its own right.
"Our spies are subject to the laws of the land, they must be held accountable by the police and the courts when they violate those laws," he said.
"I take this letter to mean the police are taking such issues seriously."