Labour claims a recording exists of Prime Minister John Key referring to Kim Dotcom during a visit to the Government Communications Security Bureau in February.
Labour Leader David Shearer said Mr Key addressed staff at the bureau during a visit on February 29th following a briefing about the GCSB's surveillance of the Megaupload millionaire.
Mr Key has already had to concede he was briefed on GCSB's involvement in the Dotcom case - a shift from his earlier claim he first learned of the links on September 17.
Mr Shearer called on Mr Key and the GCSB to confirm whether a recording of Mr Key's comments to staff in February existed and to have any unclassified material from the visit released to "clear this up".
Mr Key told TV3 he had no memory about whether he mentioned Dotcom when speaking to GCSB staff.