One of the problems with our spy agencies is that not only are we kept in the dark about what they do, we're also kept in the dark about what they think they're allowed to do. For example, while the GCSB Act apparently forbids spying on New Zealand citizens, the GCSB clearly spies on them through its full-take collection of the Pacific and claims that this is legal and authorised. Clearly, their interpretation of the law differs from the obvious one. In response, the New Zealand Council for Civil Liberties' Thomas Beagle has suggested that they publicise their interpretation of the law:
One of the issues with public oversight of an agency such as the GCSB is that we can all read the governing law but only those within the agency know how the words of the law are interpreted and put into action. Other laws get publicly tested in the courts or as they are applied, but the secrecy that the GCSB requires means that this does not happen for the GCSB Act. This leads to a gap in knowledge of the law between those within the agency and those without, and the uncertainty in this gap leads to mistrust.
However, it is my understanding that the GCSB does prepare legal analyses of the various parts of the GCSB Act so as to ensure that GCSB staff act within the letter of the law.
My suggestion is that the GCSB should make these legal analyses (edited for security reasons as required) publicly available. As these legal analyses would only discuss the publicly available law, I believe that making them public would not risk New Zealand's security.
As he notes, this would lead to a better understanding of what the spies do, and - to the extent that it seems that they are taking our privacy seriously and not weaselling around the law NSA-style - greater trust in the spy agencies. Unstated, but obvious, is the converse: refusal to publish these interpretations will lead to more mistrust and a belief that they have something to hide.