The GCSB is refusing to say whether private information from Gmail, Facebook and other other online accounts has been captured by United States spy bosses and whether they can access it.
United States intelligence agencies have been outed as running an interception programme called Prism which gives them direct backdoor access to some of the internet's biggest companies.
It followed the revelation of a secret court order which saw the National Security Agency collect massive amounts of information about Americans and their calls.
New Zealand is a member of the Five Eyes/Echelon network and the type of information being collected would be the sort shared with the United States' intelligence partners, according to National Security Agency whistleblower William Binny.
By law, the bureau cannot spy on New Zealand residents or citizens. But if the information was intercepted by intelligence partners, the law is less clear.