Security experts are questioning whether New Zealand's spy agency is processing data from an American mass surveillance programme which is capable of secretly accessing emails, online chats and internet browsing histories from around the world.
A powerpoint presentation leaked by former National Security Agency (NSA) contractor Edward Snowden to the Guardian newspaper appears to show that there are computer servers for a high-powered spy programme in the north of the South Island - where the Waihopai spy base of the Government Communications Security Bureau (GCSB) is located.
The programme, known as XKeyscore, gives US analysts power to search vast databases that hold personal information such as emails.
Computer forensic investigator Daniel Ayers, who founded IT security firm Special Tactics, said the leaked documents showed the global scale of the US spy programme.