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.
New Zealand's spy bases were already used to collect intelligence from the South Pacific and relay it to Five Eyes intelligence alliance partners - the US, Canada, the UK and Australia. Mr Ayers said the leaked document hinted that New Zealand could be a conduit for data intercepted by US spy satellites.
"Does that red dot on the map signify that Waihopai is being used to 'downlink' intercepted data from other countries? If that's the case, then it's pretty big news because I don't think that's been publicly discussed by the Government. It means our role in this is greater than we knew."
He said it also raised the possibility that US agencies were intercepting New Zealanders' communications.
Massey University academic and former GCSB senior adviser Damien Rogers said the revelation that an XKeyscore server was located in New Zealand was not in itself significant.
But it prompted questions about where data from the mass surveillance programme went and who had control over it.
What is XKeyscore?
*A mass surveillance programme run by American spy agency National Security Agency (NSA).
*Used in 700 computer servers in 150 sites across the world, one of which appears to be NZ.
*Allows analysts to access emails, online chats and the internet browsing histories of millions of people without prior authorisation.
*Described by whistleblower Edward Snowden as collecting "nearly everything a user does on the internet''.