Prime Minister John Key has spoken of people trying to use New Zealand technology to build weapons of mass destruction, to justify law changes for the Government Security Communications Bureau.
Mr Key revealed the attemped espionage as he unveiled the proposed changes to the Act governing the bureau, making it legal to spy on citizens and permanent residents of New Zealand.
He said that while he can't go into too much detail about the work the agency does, it helps to prevent international cyber espionage.
Mr Key said there have been covert attempts to acquire New Zealand science and technology for programmes relating to weapons of mass destruction or weapons delivery systems.
Mr Key said law abiding citizens have no reason to fear the agency.
On Monday, he confirmed planned changes to the Act governing the GCSB, after a report raised questions about the legality of 56 operations since 2003.
He also announced an inquiry into how the report was leaked to the media, a week before its scheduled release.
The Green Party is accusing the Prime Minister of scaremongering to get support for the law changes.
Co-leader Russel Norman said the bureau has shown to have a culture of operating outside the law.
Dr Norman said the Greens refuse to back the changes, in the absence of a wide ranging inquiry.