Every time a toilet is flushed in Brisbane's south and west it could be contributing to the fuelling of Australia's first poo-powered car.

Queensland Urban Utilities is saving millions of dollars every year as it uses the city's toilet waste to power up to 50 per cent of two of its largest sewage treatment plants, and now one of its fleet cars.

Every time Brisbane residents flush their toilet they could be helping run Australia's first poo-powered car. Credit:Paul Edmondson

QUU spokeswoman Michelle Cull said one day the sewerage and water provider hoped to have an entire fleet of cars that could run on human waste.

"At the moment we just have the one car, but yes, we do have plans to hopefully one day power our entire fleet by poo," she said.