This paper examines the tensions involved in the production, presentation and revision of hazard maps, focusing on the controversies that have become increasingly common when they are used to change government policy. Our scope includes all the major environmental hazards currently being mapped in New Zealand, one of the world's most exposed and hazard‐aware countries. Selecting one country also allowed a multi‐hazard approach to be taken that helps provide messages for other countries. Drawing on interviews with 24 key informants, the paper identifies a range of reasons for explaining the recent growth in hazard mapping and why hazard maps sometimes resulted in high‐profile controversies. Two themes emerged out of this analysis: an inconsistency in modelling and mapping hazards that created opportunity for challenge and the selective mobilisation of scientific uncertainty to dispute the legitimacy of official maps, particularly on developed land. The findings highlight the multiple roles of mapping, positioning maps as potentially instruments of both depoliticisation and repoliticisation. We emphasise how conflicts are most likely when maps are used as technocratic instruments of depoliticisation, and that creating maps in a more open way can generate valuable opportunities to engage with communities in more creative policy‐making regarding the threats they face and how they can respond. Mapping processes that open up the space for critical debate can act as important debate‐support tools as well as decision‐support tools, particularly when used to give voice to those not normally heard or treated as equal.