The Principles of Legality in Aotearoa New Zealand

The principle of legality has emerged as a central feature of contemporary public law in Aotearoa New Zealand. After a slow start, a series of major Supreme Court decisions, as well as a significant case law generated by the COVID-19 pandemic, have ensured the principle's meteoric rise. The article unpacks key elements of this dynamic jurisprudence. First, it analyses the "triggers" for the legality principle, that is the norms that enliven the principle. These have expanded significantly over time. The article examines four types of trigger: common law norms, principles of the Treaty of Waitangi, international law and statutory human rights. Second, the article examines the legality principle itself. While the principle of legality is often treated as a unitary principle, close analysis of the case law demonstrates there are multiple variants of the principle, which are meaningfully different. In turn, much of the explanation for these variations lies in the plural nature of trigger norms.