The much-vaunted electric bus transporting NSW Labor leader Chris Minns around the state in the lead-up to Saturday’s election has run out of charge.

The eco-friendly bus – packed with travelling media and Labor staffers - ran out of battery yesterday on a trip to Camden in Sydney’s west.

Minns and his passengers were forced to disembark before quickly being ushered onto a diesel-powered bus that was brought in as backup.

Sharp political watchers joked that it was the perfect metaphor for the current state of the nation’s power grid, with much-heralded renewables regularly requiring fossil fuels to save the day.

The Labor leader joked with media that he had “forgotten to charge it last night”.

Minns had boasted about the Australian-made bus at the start of his run for office, making special mention of the vehicle’s all-electric status.

Premier Dominic Perrottett was quick to jump on the problem, telling journalists: “It's no surprise that Labor's bus has broken down, just like their budget broke down yesterday.”