The Privacy Commissioner is looking into a complaint about the Government spy agency's refusal to tell an activist whether she had been under illegal surveillance.
A report released in April this year on the Government Communications Security Bureau showed as many as 88 people may have been monitored unlawfully.
At present, it is illegal for the GCSB to spy on New Zealand residents. Legislation its being put through Parliament under urgency to allow it to do so on behalf of police, Defence and the Security Intelligence Service.
Political activist Valerie Morse was one of those originally arrested in the Urewera raids case and believes she would have been spied on.
Ms Morse asked the GCSB under the Privacy Act whether this was the case, and this week received a letter stating the agency would not confirm or deny anything.
She has complained to the Privacy Commissioner, who is investigating the issue and will consider whether it will be taken further. Ms Morse says she may also consider a starting a class action.
Several other people spoken to by Radio New Zealand have also requested their information from the GCSB, but are yet to hear back.
John Edwards, a barrister specialising in privacy law, says once people take their claims to the courts or the Privacy Commissioner there may be no grounds for the agency to withhold the information.
Mr Edwards says it may have to come clean on cases where it was monitoring people as part of a police prosecution.
In response to Radio New Zealand's questions, GCSB director Ian Fletcher said in a statement that to confirm who or what the agency might have been investigating, or not investigating, would potentially identify law enforcement or national security priorities, which is not appropriate.