A power supply issue is affecting the Sydney Metro as the afternoon peak begins.

Due to the technical incident at Chatswood, metro services are not running between Macquarie Park and Barangaroo, effectively stopping commuters from using the line to cross the harbour.

Services are still running between Tallawong and Macquarie Park and between Sydenham and Barangaroo.

Commuters have been told to check the Transport for NSW website before travelling and allow for extra travel time.

"We apologise for the inconvenience," a transport spokesperson said.

More to come...

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