An urgent authorisation for warrantless surveillance has been reviewed by the Inspector-General of Security and Intelligence and has been found to have no "material concerns".
The Security Intelligence Service (SIS) used the authorisation to respond to a suspected terrorist act for the first time in the second half of last year.
A 2014 law change gave the agency the ability to carry out surveillance without a warrant for up to 24 hours, if it believed that was necessary "for the detection, investigation, or prevention of any actual, potential, or suspected terrorist act, or facilitation of a terrorist act".
At the time the minister responsible for New Zealand spy agencies, Chris Finlayson, would not confirm the circumstances that led to the authorisation but said the use of warrantless surveillance was pretty rare.
The SIS successfully applied for a warrant within the 24 hour period to continue the surveillance.
In her 2015/2016 annual report, the Inspector-General of Security and Intelligence (IGIS), Cheryl Gwyn, said she had reviewed the authorisation.
She said she found no major problems, except to tell the SIS it "could have been framed more clearly".
There were no further details about the situation that prompted the urgent authorisation.
GCSB 'self-reported' four investigation results
The IGIS also reported the Government Security Communications Bureau (GCSB) 'self-reported' the results of four completed investigations, and seven other possible incidents of possible non-compliance.
Each of the four investigations relate to cyber-security activities or intelligence gathering activities, so Ms Gwyn said she was limited in details she could reveal.
However, she could say one related to a "potential error in reporting of historical unlawful intelligence-gathering" but that further inquiry would be "frustrated by poor past documentation and incomplete historical records".
Despite noting the director has concluded there was "no credible reason to believe there was unlawful intelligence-gathering", Ms Gwyn is currently considering whether it was "possible and, if so, necessary " to inquire further into this.
She was satisfied that "inadvertent error, rather than systemic deficiency" were to blame in the incidents covered by the other investigations and that there was "no material adverse consequence".
Ms Gwyn expected to receive reports on the other seven incidents and report on them next year but added "at this stage, in my view, these are only potential incidents and do not indicate actual non-compliance".
She said she would take any necessary steps if any pressing concerns arose as the result of either the GCSBs review, or her own investigation.
Need for prompt reporting on director's authorisations - Cheryl Gwyn
Ms Gwyn also reported the GCSB executed 15 interception warrants, and 30 access authorisations.
She also noted there were several director's authorisations, which allow interception of non-New Zealand communications of high-frequency radio signals by ships or other radio operators, and covers the satellite communications interception station, Waihopai, and Tangimoana.
These were signed off by the director during the reporting year that did not come to her attention until after 30 June.
Her report said her office "discussed with Bureau the need for prompt notification to her office of Director Authorisations".
In her 2014/2015 annual report, the IGIS detailed 29 domestic surveillance warrants as well as "all of the foreign intelligence warrants", but at the request of the SIS she did not say how many there were.
Ms Gwyn cited the view of the SIS Director that putting a number on foreign intelligence warrants "raises issues both of of legislative intent and of possible security or international relations risks that require further discussion".
In this latest report, with the agreement of the SIS, the IGIS reports 18 foreign intelligence reports were issued in the year to June 2016.
Included in the surveillance warrants were one domestic visual surveillance warrant, and the one urgent authorisation for domestic warrantless surveillance.