Auckland trains have been disrupted by a tsunami warning.

Auckland trains are now running to schedule after disruptions to all lines on Friday morning, due to a tsunami warning.

The Newmarket to Britomart line was closed as a precaution following a large earthquake off East Cape, causing a back up at Newmarket station.

At 9am, trains city-wide were delayed by 5-10 minutes and running at 20 minute intervals, but by 10am services were back to normal.

Auckland Transport spokesman Mark Hannan said the decision to close the busy line came down to KiwiRail, the line's owner, as a precaution.

UPDATE: Train services across the network now running to schedule. Thank you for your patience this morning and sorry for any inconvenience. — Auckland Transport (@AklTransport) September 1, 2016

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Commuter disruptions were felt in peak travel times as the western and southern lines terminated at Newmarket station, instead of Britomart.

Despite this, Hannan said there were "plenty of bus contingencies" to move people to where they needed to be.

"We were getting people to Newmarket and there are very good bus links from Newmarket."

The Britomart station and Newmarket to Britomart train link was reopened shortly before 7.30am.

Earlier, services on the Onehunga line were suspended, while the eastern line was only operating between Panmure and Manukau.