Invasive species threaten the health, safety, sustainability, wellbeing, and prosperity of Aotearoa New Zealand. A key function of the biosecurity system is to comprehensively assess the risks posed by invasive species. This study investigated the psychological dimensions of biosecurity risk assessments and explored potential targets and mechanisms for improvement. Twenty participants were recruited from Aotearoa New Zealand’s biosecurity workforce. Policy capturing, multiple-criteria decision analysis, and the behaviour change wheel were used as investigative frameworks. Results from the policy capturing analysis indicated that risks to economic, environmental, sociocultural, and te ao Māori values all significantly increased participants’ perception of invasive species’ overall biosecurity risk. Risks to economic values had the largest effect and risks to sociocultural and te ao Māori values had the smallest effects. Results from multiple-criteria decision analysis indicated that participants consciously allocated the most importance to risks to economic values followed by risks to environmental, then sociocultural, and then te ao Māori values. Results from the behaviour change wheel analysis indicated that participants were motivated to incorporate te ao Māori values into their biosecurity risk assessments but perceived that they lacked the capability and opportunity to do so. Key intervention targets and mechanisms were discussed to address these areas and support comprehensive biosecurity risk assessments.