Spy boss Ian Fletcher has denied Labour claims that Prime Minister John Key was caught on camera discussing Kim Dotcom in February.

Earlier today Labour claimed a tape existed of Key giving speech to staff in cafeteria at the Government Communications Security Bureau’s Wellington headquarters in which he made a quip about Dotcom. Key has said he remembers the speech but not the remark.

Fletcher said "exhaustive enquries" at the GCSB have revealed no video tape. Still photographs exist but would not be released because they identify staff at the super-secret agency.

An investigation was now underway into the ‘‘leak’’ at the agency, he said.

"The department has made exhaustive enquiries of its records and its IT systems, and can find no audio-visual recording of the Prime Minister’s visit to GCSB on 29 February 2012," he said in a written statement.

"An investigation has commenced within GCSB as to whether there has been any unauthorised disclosure of information, and if so, its source."

Key has said he first learned of the involvement of the GCSB on September 17. But it emerged last week he was told about their surveillance on Dotcom at a briefing on February 29. He accepted he was told but didn't remember the reference to the millionaire internet entrepreneur.

Labour leader David Shearer had called on the GCSB or Key to confirm if the recording existed.

“There is one way to clear this up. The Prime Minister should give the green light to the agency to release any and all unclassified material about the visit and John Key’s comments to staff,'' he said.

Shearer wants a ''full inquiry'' into the GCSB's role on Operation Debut, the joint FBI-police raid on Dotcom's home in January. United States authorities want to extradite him on internet piracy charges.

Key has lashed the GCSB for a series of bungles over the Dotcom case which have left him politically exposed. It emerged last month they had illegally spied on Dotcom and one of his co-accused, who are protected as New Zealand residents.

- © Fairfax NZ News