This study began as a simple inquiry into why a certain type of pressure group, the cause group, as opposed to the economic interest group, existed in the New Zealand political system. It was prompted by the writer's observation that many of these groups continued to exist although apparently they were not successful in fulfilling their (stated) aims. This thesis, then, examines three established New Zealand cause groups, Citizens’ Association for Racial Equality (Auckland), Committee on Vietnam (Wellington) and the Campaign Against Rising Prices (Wellington); and looks at their changing or unchanging goals to answer the question "Why do they still exist?" The answer that emerged was that these cause groups are not motivated by success in conventional political terms: rather that they continue because they regard their existence as a necessary alternative to the established political channels. Necessary, that is, for the electorate rather than for the established channels: but nonetheless advantageous to the political system as a whole. One further point emerged from this study: that cause pressure groups are a demonstrably separate phenomenon from economic interest groups.This points towards a lack of clarity and discipline in existing pressure group theory and calls for further investigation into this area.