Public participation is a desirable and necessary component of any decision-making process regarding the allocation of resources. In its present form, however, it is not as effective as it could be. The aim of this study is to develop a strategy leading towards effective public participation. The study focuses primarily on the participants. Criteria are developed for discerning their effective involvement in a decision. The criteria are: 1. the achievement of the individual's or the interest group's objectives; and 2. the influence the participants have on the decision or decision-making process. These criteria are applied to six interest groups who participated in the recent Rakaia River National Water Conservation Order Hearing. It is concluded from this examination that participants are more likely to be effective in their participation if they have experience in participatory exercises, access to all information, good relations with the media, professional assistance and dedication to the issue. The need for a clear and effective natural resources policy to guide decisions of resource allocation is also proposed in this study. There is also a need for a greater recognition of the importance of public participation in social and environmental impact assessment procedures. Effective public participation is a goal often sought but not often achieved. Public awareness, public education and the initiation of independent evaluators for public participation programmes would provide the basis for a strategy of more effective public participation.