Internationally, introduced invasive species inflict incalculable damage on native species and primary production. In New Zealand, wallabies, which were introduced from Australia, are damaging the native and agricultural environments, and their range is spreading. As a first step towards the long-term goal of eradicating wallabies from New Zealand, the Tipu Mātoro National Wallaby Eradication Programme has the immediate goal of restricting wallabies to containment areas designated in regional pest management plans and to eliminate outlier populations by 2025. The success of this strategy is put at risk if people catch wallabies and release them outside the containment areas. We sought to characterise the motivations, beliefs, and attitudes of members of the public who might engage in this illegal behaviour by surveying members of the New Zealand public. We discovered that a very small proportion of the public supported the illegal catch-and-release of wallabies. Respondents, including hunters, that supported catch-and-release believed that wallabies create economic benefits and do not severely damage the environment. They also believed that hunting helps control wallaby numbers. These results yielded a variety of specific policy implications required to reduce catch-and-release behaviour.