This article aims to facilitate debate about the implications for New Zealand social policy making of taking a rights-based approach. It does so by exploring the sources and scope of New Zealand’s international human rights obligations, particularly in relation to economic, social and cultural rights. It identifies a range of constraints on social policy making deriving from these obligations and suggests that explicit and systematic attention to these constraints constitutes the essence of a rights-based approach to social policy making. Finally, the article comments on the adequacy of existing processes and structures of New Zealand government for giving effect to a rights-based approach and makes some suggestions for how these might be modified.