Threats of natural and deliberate biological agent release are very real and are of serious concern within Australia and internationally, having the potential to substantially impact human, plant and animal health as well as agriculture, trade relations, infrastructure and the economy. Biosecurity programmes and policies are essential for counteracting these threats and enabling a nation to effectively prevent and/or respond to the natural, accidental and deliberate release of a biological agent. The major biosecurity focus in Australia is the protection against invasive animal, plant and insect species; however, more recently, the threat of microbiological agents has become a priority for Australias national security. Australias biosecurity capabilities are maintained through a coordinated effort, involving national, state and local government and non-government agencies. Communication and collaboration between all parties, at both a national and international level, is the key to an effective response. The threat from biological agents is a very real concern and Australia must maintain its preparedness in order to ensure its capacity to respond to biological threats. This review provides a contemporary overview of biosecurity in Australia and the role of forensic science in the investigation of biosecurity incidents.