Motorists and public transport passengers should stay away from the Sydney CBD until further notice.
Anyone already in the city should follow the directions of emergency services personnel and transport staff on the ground.
Roads are closed between George Street and Macquarie Street from Park Street to Circular Quay.
Bus services using George Street are running.
Harbour Bridge bus services are running but terminating at Wynyard.
Other services are affected by the road closures so passengers should catch services at designated temporary bus stops.
As well, passengers are able to use their bus tickets on all train lines and ferry services.
Trains continue to run, however trains on the T4 Eastern Suburbs & Illawarra Line are not stopping at Martin Place.
Passengers are able to use their train tickets on all Sydney Buses and Sydney Ferries.
Passengers are advised to allow plenty of additional travel time and continue to stay away from the Sydney CBD.