Rapid international travel times and the arrival of new and unexpected infectious disease threats have demonstrated that, for effective communicable disease control, Australia's response needs to be flexible and coordinated. This paper summarises how our public health and clinical systems would respond to a case of Middle East respiratory syndrome (MERS) coronavirus and our responsibility under the International Health Regulations to notify the World Health Organization (WHO). It also describes the processes undertaken by WHO when it declares that a disease outbreak is a Public Health Emergency of International Concern. Australia has robust communicable disease response systems, tested by new threats for many years, which are under constant review and improvement.