3.2However, disclosure obligations have limits. The common law has long recognised the importance of protecting other interests, such as national security or the continued use of sensitive Police investigative methods.93 These exceptions are now contained in statute.94 Where one of the statutory grounds is met, information can be withheld or released in a modified manner (such as through anonymous witnesses giving evidence behind a screen where they may be at risk if their identities are divulged).
3.3An important part of the background to this discussion is the need to ensure that our judicial system has the necessary tools to manage the trial of someone accused of a terrorist activities, in which national security information forms a key part of the evidence (for example, linking the individuals accused of a terrorist act in New Zealand to overseas terrorist entities). While this review is not focused exclusively on such cases, it provides an opportunity to examine current mechanisms for protecting security evidence if a case of this sort was ever to occur in New Zealand. As will be discussed further below, the Criminal Disclosure Act 2008, the Criminal Procedure Act 2011 and the Evidence Act 2006 provide grounds for withholding evidence that raises national security risks. This chapter will consider whether there is a need for additional mechanisms to protect national security information in criminal proceedings, taking account of the fundamental importance of ensuring a fair trial while also giving law enforcement agencies the necessary tools to protect public safety through investigating and prosecuting offences.