Fresh US security information released by whistle-blower Edward Snowden appears to suggest the GCSB is using New Zealand embassies overseas to conduct covert intelligence gathering.
Amidst a raft of NSA documents posted on the Intercept website over the weekend, is one labelled "Exceptionally Controlled Information".
It's listed as top secret and appears to document some NSA operational details and codes.
Within it is a listing called STATEROOM, which talks about "restricting access to information about personnel involved in the covert collection and processing of SIGNIT (signals and intelligence) from Diplomatic missions abroad".
It goes on to say that "this activity is conducted by US, AUS, CAN, GRB and NZ" all of which are members of the Five Eyes spy network.
The GCSB says it does not comment on matters of intelligence and national security.