It is apparent from existing research that little is known about the effectiveness of non-union employee representation (NER) voice arrangements in Australian firms. This article examines both the non-union Suncorp-Metway Employee Council (SMEC) and union voice arrangements at an Australian financial services firm, Suncorp, and assesses their effectiveness in representing the needs of employees. This study is unique because it is one of the few examples of dual representation channels at a single firm. Overall the findings suggest that the effectiveness of union and NER arrangements is dependent on the union and NER voice channels being perceived by the workforce as both representative and able to act effectively or independently. However, while trade unions may provide greater voice than non-union arrangements, the strength of voice is dependent on the legitimacy and effectiveness of trade unions in representing employees' interests at the workplace. The findings also suggest that the marginalisation strategy used by the union in excluding SMEC from its industrial campaigns, coupled with employees' perception of a lack of effective union voice, could impact negatively on the influence that unions may have on management decision-making. This could also be perceived by employees as an inappropriate response by the union to management substitution strategies. As a consequence, any changes to industrial relations policy or trade union strategies regarding NER should be considered in the light of these findings.