As nursing has developed as a profession there has been a continual evolution of the scope of practice in which nurses work. Emergency nursing practice is an example where recently there has been a rapid expansion in the nature and scope of practice. This change in practice has largely resulted from increasing public demand on emergency departments, medical and nursing shortages and governmental pressure to reduced emergency department waiting times and patient length of stay. There have been a number of models worldwide in which the expansion of the Emergency Nurses role has occurred. Recently in New South Wales the Clinical Initiative Nurse role has been developed as an advanced practice role with the objective of initiating treatment based on advanced clinical assessment and to assist emergency departments to meet benchmarks and key performance indicators (KPIs). The scope of practice of this new role did not extend to that of a Nurse Practitioner who is able to discharge patients, prescribe medication and provide medical referral. The variation in advance practice nursing roles in Australia and worldwide has contributed to confusion and uncertainty. The aim of this paper is to explore the various advanced practice roles that may be encountered in emergency nursing practice and examine some of the advantages and limitations to the implementation of these roles.