Australia's vast tropical savannas contain outstanding biodiversity and cultural values. The region supports many industries, with broad-scale pastoralism being the most widespread. Hundreds of plant species were introduced into northern Australia to support the pastoral industry; some species have since been termed 'contentious' or 'conflict' species due to their perceived positive value for industry but negative impacts on non-pastoral values when they invaded non-pastoral landscapes. Heated political and public debate ensued about the appropriate policy and management response to these species based on people's perceptions of values being altered by invasion by these species, and conflicting views on what constituted appropriate management actions to control their use and spread. Here we share our insights into the role of scientific evidence in progressing this debate, by quantifying the impacts of species on environmental, socioeconomic and cultural values. We reflect on the importance of science for underpinning evidence-based risk management tools, the outputs of which supported policy response by politicians and other policy decision-makers. We also assess the gap in translation from policy to coordinated on-ground action at the national scale, and provide our insights into the contribution that science can make to bridging this gap.