Disaster drill underway in Sydney

Police and emergency workers have converged on Barangaroo in inner Sydney for a major role-playing exercise.

The drill simulates a Boeing 777 crash with 500 casualties and is the largest such exercise in the state's history, according to Emergency Services Minister David Elliott.

"We need to make sure as a government that the people of NSW are confident that regardless of the accident, the incident, the activity, that all of our emergency services work hand in glove together and (are) well resourced," Mr Elliott told reporters on Sunday.