Air force planes kitted out with high-tech military equipment are being used to help investigate crimes.
The air force's six P3-K2 Orion aircraft are going through a $373 million upgrade, with three already operating with upgraded systems.
They include infrared sensors, radar which is capable of tracking distant "targets" on the ground and a camera kit which can pick out faces from kilometres away.
A Royal New Zealand Air Force publication revealed one of the aircraft had been kitted out with full motion video gear to assist with the Rugby World Cup - although it was never used.
The Herald sought further details of how the plane was used in domestic policing operations. The air force refused to supply details, saying it could hamper efforts to detect, investigate and prevent offences. Details could also affect the ability of people facing charges to receive a fair trial.
Defence chief Lieutenant General Rhys Jones said the requesting agencies were responsible for ensuring surveillance warrants were obtained and that it was within the law. He said the NZ Defence Force was not covered by the legal definition of "law enforcement agency" under laws which controlled powers of search and surveillance but was "mindful of the need for compliance" with the law when helping others.
"Where asked to provide assistance to a law enforcement agency such as NZ Police, NZDF conducts surveillance in support of that agency in accordance with the extent of the request," General Jones said.
Other agencies, including Customs, Maritime NZ and fisheries authorities, also sought help from the Orions.
Police headquarters refused to reveal details, saying operational support from the military was a long-standing arrangement. A spokesman said: "Such requests are made on a case-by-case basis and are subject to approval at senior level by both police and NZDF, and must comply with all legislative requirements."
NZ Council of Civil Liberties secretary-treasurer Kevin McCormack said the failure to supply broad descriptions of the type of support offered raised questions.
"It is entirely appropriate there be transparency. The ways in which organisations seek to avoid it often leads to the questions of whether they have something to hide."
He said police or the air force could consider telling the public the type of operations in which military surveillance was needed, if not details which would threaten particular operations.
What is the P3-K2 Orion?
It is an integral part of the RNZAF's fleet. The first five of six aircraft arrived here in 1966. The fleet is part way through its third major makeover with a $373 million refit putting in the latest electronics, giving it a front-line surveillance ability.
What's so special about the upgrade?
The upgrade overseen by US military contractor L3 expands the aircraft's abilities from maritime patrol to airborne surveillance. It can track targets on land and sea from kilometres away, using laser-guided cameras to zoom into exacting detail, even picking up faces. It is also equipped to collect electronic intelligence.
What do police use it for?
We don't know. Police ruled out surveillance relating to the Rugby World Cup and Kim Dotcom, around which questions remain over police sourcing a live video feed to the raid. The P3-K2 is used for maritime surveillance but its preparation for the RWC raises questions about its use on land.
Is it legal?
The air force says it requires any agencies it supports to get the paperwork in order, which the police assure is the case.
What other surveillance tools do the police use?
Remote-control drone aircraft have been used on some operations. They also use a social media scanning tool called Signal, which lifts publicly accessible details from the internet. Other technology includes automatic licence plate scanning and cross-referencing with police computers.