Kim Dotcom's legal team is today fighting a decision barring him from knowing what private conversations the GCSB intercepted while monitoring him.

The Government Communications Security Bureau has previously admitted illegally intercepting private communications between Kim and Mona Dotcom, and his Mega colleague Bram van der Kolk, as part of the extradition case being built between December 2011 and March 2012.

Stuart Grieve QC, who was appointed to the case, has documents listing the types and dates of communications, but Dotcom has received only a redacted version.

"Mr Dotcom, I'm afraid to say, just literally has a series of blank pages," Crown lawyer David Boldt told the Court of Appeal in Wellington this morning.

Dotcom wants the raw content of the recordings to be released.

His lawyer, Ron Mansfield, said they did not know how the communications were intercepted, including whether a phone line or internet line was tapped, whether the house was bugged, where in the house the communications were being intercepted, and so on.

"We don't know how they've conducted the conduct which they accept was unlawful," he said.

"The communications themselves will inform us as to the comprehensive nature of it, or not... one cannot assess the breach of privacy in this case without access to the words which were unlawfully intercepted by the GCSB.

"How can someone set out what their loss was without knowing exactly what the harm was?"

Boldt said it wasn't necessary to get down to such a level of detail to determine the nature and scope of the intrusion.

He took the position that every relevant document had already been provided to Grieve. He cannot use those documents in court, and make submissions on them, though.

Dotcom's team earlier took the case to the High Court, arguing they should know which conversations were monitored, and how, so they can appeal for damages.

But in a ruling last year, Justice Murray Gilbert said the recordings would not be released.

Lawyers for the GCSB argued at the time that releasing the material could prejudice the security of New Zealand, and the confidence of other countries in entrusting sensitive information to New Zealand.

The Dotcom team said any national security issues shouldn't stop the information being released, because information on the sources and methods of intelligence-gathering were already public knowledge.

A main reason for Justice Gilbert's decision is a 2013 Court of Appeal verdict that ruled the GCSB didn't have to release the raw communications. Justice Gilbert said that meant he couldn't relitigate the issue.

The judges have reserved their decision on today's appeal.