The study investigates the need of surveillance during mass gathering events in Wales, UK. An evidenced based risk assessment tool is designed to identify the risk level of an event by grading risk variables present during the occurrence of event. This tool was observed consistent when compared with the international events. The need for a continuous surveillance is associated to the risk level of the mass gathering event. Enhancing the current surveillance system to establish a collaborated department would require less resources to monitor events and for training in emergency conditions.