UPDATE: At 11.45am the police operation concluded, with some services starting to move. Delays are ongoing, with platforms and stopping patterns subject to change. People are advised to check indicator screens and live apps for more information about service delays.
Trains have currently stopped operating near Redfern Station following a police operation.
According to Sydney Trains, there is a person trespassing near the tracks, with trains halting service due to the disruption.
Passengers are advised to allow plenty of travel time on the T1 North Shore, Northern and Western Line, T2 Inner West and Leppington Line, T3 Bankstown Line, T8 Airport and South Line, Blue Mountains Line, Central Coast and Newcastle Line and South Coast Line.
Transport NSW is advising that people should consider delaying their trip if possible or make alternative travel arrangements.
There is no current forecast for when train services will resume.