The mandate for making decisions on allocation of freshwater resources in New Zealand has been devolved to regional councils by the Resource Management Act (RMA) enacted in 1991. Growing demand for water resources in many parts of New Zealand during the last two decades has increased competition and conflicts between different stakeholders for access to scarce surface water and groundwater resources. However, while the RMA planning framework is innovative in a number of important respects, regional councils have evidently found it difficult to satisfactorily address water conflicts within the framework of the RMA. The objectives of this paper are twofold: to review the architecture of current institutional arrangements and related planning practices to allocate freshwater resources in New Zealand under the RMA framework; and to comment on the potential of innovative approaches which could be incorporated within the RMA institutional framework to allocate freshwater resources. From social equity and environmental justice perspectives, it could be argued that access to water should be treated as a basic human right and as a social good for purposes of satisfaction of domestic and livestock needs and for protection of ecological integrity. At the same time, growing competition by New Zealand's wealth-producing activities, such as farming and manufacturing, for access to water makes it imperative that water is also managed as an economic good. We have argued in this paper that institutional inertia, in terms of formal and informal institutional constraints on water governance, is a major barrier to realising the innovative potential of the RMA's water planning provisions. The institutional constraints on RMA water planning practices highlighted in this paper need to be partly addressed through central government policy interventions that extend strictly beyond the RMA. The Sustainable Water Programme of Action has put forward potentially the most ambitious water reform agenda for New Zealand since the enactment of the RMA in 1991, but it remains to be seen to what extent political intentions for effective and efficient allocation mechanisms are translated into policy. The proposed reforms are limited in scope because they eschew a number of the wider-ranging institutional reforms needed to address sustainability objectives.