Almost seven years after the tragedy at the Pike River mine, the Supreme Court of New Zealand declared that an unlawful bargain had been made to stifle the prosecution of the mine’s CEO. This thesis analyses the issues that remain unresolved by the Osborne Supreme Court decision, and uses comparative jurisprudence to highlight the deficiencies of New Zealand law’s position in relation to the judicial review of prosecutorial discretions. The conclusion to the analysis is the finding that some of the public law values that underlie judicial review, namely: the rule of law, the safeguarding of individual rights (including those of victims), accountability, consistency and certainty in the administration of the law are not sufficiently protected by the current New Zealand law. The contextual constraint of requiring ‘exceptional circumstances’ as a pre-condition to intervention, represents a judicial initiative to apply the intensity of review of prosecution discretions to the lower end on the reviewability spectrum, the lowest being non-justiciability. That prevailing approach is unstructured, meaning that the exercise of prosecution discretions may be anomalous or demonstrably wrong and yet insusceptible to judicial review. On the face of it, the ‘exceptional circumstances’ test requires an extremely high evidentiary threshold. A more principled approach is to modulate the appropriate intensity of review by using explicit calibrations or variable intensities on sliding scales depending on the nature of the issues engaged. This would enable courts on a more nuanced basis than the blunt instrument of the ‘exceptional circumstances’ test, to cautiously balance appropriate vigilance with appropriate restraint. The case law has in practice ring-fenced justiciability exclusively to the ‘illegality’ branch of review. The other orthodox grounds of review have been hypothesised by the courts as being available but have been very restrictively conditioned by potent dicta, so as to make them only likely to succeed in the very rarest of circumstances. That prevailing judicial ethos is critically examined for its compatibility with principle. The dissonance between New Zealand decisional law and the well-established approach in other jurisdictions, to markedly different effect, is identified. One crucial consequence is that victims are left without sufficient rights in the prosecution decision-making phase and have only limited access to justice. This thesis provides recommendations intended to offer some principled guidance post-Osborne: a renaissance of approach to this critically important (but generally overlooked) frontier of public law.