GCSB boss Ian Fletcher has confirmed former Green MP and activist Keith Locke was not among the 88 New Zealanders his bureau may have spied on illegally.
Mr Fletcher made the rare admission after initially refusing to answer, prompting Mr Locke to take the matter to the Privacy Commissioner.
In a letter to Mr Locke last week Mr Fletcher confirmed he was not spied on.
Mr Locke posed the question after a report by senior public servant Rebecca Kitteridge uncovered a string of issues around the spy agency's compliance with relevant legislation.
Her report prompted an overhaul of the legislation which was concluded yesterday with the passing of the Telecommunications (Interception Capability and Security) Act.
Mr Locke said he asked whether he had been spied on by the GCSB due to the fact that "during the time period of the GCSB's illegal spying I was subject to SIS monitoring of preparations for my peace monitoring trip to Sri Lanka as an MP in October 2003, as reflected to two SIS reports added to my SIS file on 10 September 2003 and 24 September 2003."
Mr Locke received a copy of his SIS file in late 2008.
"It was possible that the GCSB had assisted the SIS in this monitoring, particularly as the GCSB is involved in monitoring international communications and receives information from its Five Eyes partners on such communications."
Mr Locke said he was please to finally get the information from Mr Fletcher, "and I hope that GCSB now adopts a policy of more reasonable openness to requests from others who ask whether they are among the 88 people".
Asked whether Mr Fletcher's decision indicated he would provide an answer to similar questions from others, a GCSB spokeswoman said: "We consider each request on its merits, and if a requester isn't happy with a response they can take it up with the Privacy Commissioner''.