The country's internal intelligence agency has a special protocol for spying on journalists, the Prime Minister's office has confirmed.
The revelation of the protocol came in a letter which effectively confirmed journalists as valid targets for NZSIS surveillance.
The Herald sought details from John Key's office on the intelligence community's attitude towards spying on the media. The request followed revelations of mass surveillance coupled with overseas spying on media for intelligence leaks.
In recent days, the rights of media have been strongly defended after claims a reporter was spied on in Afghanistan by the NZ Defence Force and revelations a press gallery journalist's phone records were handed to a leak inquiry.
The Herald learned details through the Official Information Act which an intelligence community source said needed to be seen in the context of those who classed themselves as journalists.
He said it was an extensive grouping of people which could include dangerous or radical elements.
The response from the Prime Minister's chief of staff Wayne Eagleson provided scant details saying the intelligence agencies needed to work in secret.
But the few details provided ruled the Government Communications Security Bureat out of spying on journalists - and appear to confirm journalists had been targeted by the NZ Security Intelligence Service.
Neither intelligence agency offered details on the warrants - which need ministerial sign off - saying New Zealand's national security would be imperilled were details of spying methods or targets be revealed.
Mr Eagleson said the GCSB was governed by law which made it illegal to spy on a New Zealand citizen or resident. It was the same section of the law criticised as being unclear and needing the current controversial changes.
The Herald also asked for information about briefings Mr Key had received as minister in charge of the agencies. Mr Eagleson said the GCSB told him there had been no briefings about surveillance on journalists, refusing the request using a section of the Official Information Act which states the information sought does not exist.
But when it came to the NZSIS, the information sought apparently did exist because the reasons given for refusing to provide it stated there was something to be revealed. Whatever that might have been was not supplied - the NZSIS told Mr Eagleson revealing details would place New Zealand in danger or upset international relations.
However, the NZSIS did tell him its "Investigations Policy outlines the process before any investigation is commenced into a journalist" to make sure legal protections under the Evidence Act are not breached. The act allows journalists to withhold sources in court cases unless a judge decides the public interest is better served revealing their identity.
While referring to the check on the Evidence Act, Mr Eagleson said it did not bar the NZSIS as it was only prohibited if they were legally privileged, from religious leaders, doctors and clinical psychologists.
A spokeswoman for the NZSIS said all people could be subject to a warrant but criteria were strict and "there must be a genuine reason to believe the individual is a threat to national security".
"This assessment is based on behaviour rather than on an individual's occupation."
"NZSIS understand and respects that journalists also have a very important role in a free and democratic society. NZSIS has internal policies in place to ensure any proposal to investigate an individual who holds a central role in democratic society, such as journalists and members of the judiciary and parliament, are treated with additional sensitivity."
The NZSIS had 34 domestic interception warrants for the year ending June. Of those, 12 remained in force from the previous year.