Sydney Metro power outage strands commuters in heat and darkness

Sydney commuters have been left frustrated and their work days delayed after being stranded in a driverless Sydney knocked out by a power outage.

Commuters said they were stuck on the train at Norwest station on the Sydney Metro line for more than an hour

A NSW Transport Management Centre told 9news.com.au a power outage at Kellyville, near the northern end of the line which connects north-west Sydney to the city, was to blame for the 40-minute peak commute meltdown.

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"We just sat there and waited and waited," commuter Matt Hannah told 9News.

Hannah said despite the frustrating delays commuters made a joke of the power outage leaving them in darkness.

"Everyone was making a joke of it and saying they forgot to put money in the machine," he said.

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Commuters said the power outage caused the air conditioning to turn off more for a short period of time while the mercury started to climb to 30C outside.

"It got very warm in there, the lights kept switching on and off," commuter Viv Rajakkal told 9News.

All while the commuters waited in darkness with the growing heat, Rajakkal said there was just a repeated message about technical issues on the line.

Another commuter said it was just the "stock standard" of delays on the city's public transport.

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Other passengers took to social media to complain about the long delay during peak hour.

"So it's been an hour and 20 minutes since the metro stopped working at Norwest…now we have no power and no air," one woman posted on Twitter.

"Ben (sic) sitting on metro at Norwest station for over an hour now. Power just went off for the 3rd time and aircon off - full train," another passenger complained.

Services are now running again but delays are expected.