Plant biosecurity outbreaks are known to disrupt agricultural industries and cause substantial damage to farming businesses. Farmers have been hit particularly hard by such incursions due to loss of production, income, and the risks to their reputation of growing premium produce. To mitigate the negative impact of biosecurity incursions, farmer biosecurity risk management strategies are vital. However, the reasons of why or of which farmers may take actions against biosecurity incursions are not well-understood. In this study, we applied the Protection Motivation Theory to identify factors influencing farmer intention to undertake biosecurity management strategies. A survey was carried out between 2015 and 2016 across 101 Vietnamese farmers in three locations in Australia: the Northern Territory, South Australia, and Western Australia. Following data analysis using factor analysis and stepwise regressions, the results showed that farmer self-efficacy of on-farm risk management strategies, available incentives, and belief in biosecurity threats associated, positively, with the intention to adopt biosecurity risk management strategies, while expected response costs demotivated intention. Farmers with more farming experience were less likely to adopt biosecurity risk management strategies. To effectively facilitate farmer intention to adopt protective biosecurity coping measures, policies need to be targeted at the right farmers. Promotion of farmer uptake of biosecurity risk management strategies is needed to ensure well nurtured and sustainable plant industry in Australia.