Weeds have long been identified as a threat to agriculture and human health and, more recently, as a threat to the environment. In order to address these threats, a two-pronged approach is required, encompassing the prevention of weed introductions and the control of existing weed infestations. Regulation is necessary to achieve this control. The regulatory and policy regimes for both prevention and management of weeds are analysed, with a particular focus on the scope and implementation of week management under the Noxious Weeds Act 1993 (NSW). The legislation relating to the prevention and management of weeds is found to be broad in its scope. However, the potential scope of the legislation is not being fully realized, due to current policy, the interplay with other regimes, international politics and practical issues such as insufficient funding.