The Green Party says it would not be surprised if the US National Security Agency has sent back information on New Zealanders.
The NSA has been identified by a whistleblower as conducting a clandestine surveillance operation that monitors computer and telephone networks around the world.
The Guardian newspaper has revealed the man is Edward Snowden, a technical worker at the CIA. Last week, The Guardian and The Washington Post reported that American agencies gathered millions of phone records and monitored internet data under a programme called Prism.
Greens co-leader Russel Norman told Checkpoint on Monday that theoretically, there are constraints around spying on New Zealanders, but the use of US surveillance data could be a way to get around that.
"We've all now got this data about us stored in the United States by the NSA and what we don't know is how many reports and how much data was fed back to the New Zealand security agencies.
"In the United Kingdom, the reports in The Guardian suggest there were about 200 reports from this thing called Prism back to the UK government in one year."
Prime Minister John Key said on Monday there may be isolated cases where it is in New Zealand's interests to work with other intelligence agencies to gather data - but no wholesale, reciprocal work is taking place - and any intelligence gathering is done within the law.