Major delays across multiple Sydney train lines over 'staff resourcing issue'

Commuters have been warned to consider alternate modes of transport or risk major delays along Sydney's busiest train lines this afternoon over what officials say is a "staff resourcing issue".

People hoping for a smooth trip home after work may need to reconsider their plans, with trains along the T1 Western and T5 Cumberland Lines having completely stopped in both directions.

Both the T1 North Shore and the T2 Inner West and Leppington lines have been affected by the issue, with authorities warning of delays of at least an hour.

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"A limited number of buses are replacing trains between Parramatta and St Marys, and between Parramatta and Richmond on the T1 Western Line, the T5 Cumberland Line and the Blue Mountains Line due to a staff resourcing issue," a spokesperson for Transport NSW said.

"Sydney Trains apologises for the inconvenience and thanks our passengers for their patience."

Sydney Trains said on Twitter: "Allow up to 60 minutes extra travel time due to a staff resourcing issue earlier.

"Services may be less frequent and trips may take longer than usual.

"Stops may change at short notice."

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Uber and other rideshare providers have been warned to expect a spike in job requests.

Large crowds have begun to pile up at Parramatta and St Marys stations, where queues for replacement busses have swollen.

More to come.

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