ONE of Australia's favourite cars, the Holden Commodore, has topped a new Federal Government list of bad environmental performers.

An online vehicle guide (www.greenvehicleguide.gov.au) launched at the weekend lists the Commodore as having the highest fuel costs - $2430 a year - and largest greenhouse pollution output - 3.8 tonnes - of the top five selling cars. It is followed by the Ford Falcon which costs $2272 in petrol a year and produces 3.6 tonnes of greenhouse gases.

Hybrid cars such as the Toyota Prius and the Honda Civic hybrid were the best performers, producing only 1.6 tonnes of greenhouse pollution a year each and having petrol costs of only about $1000 each.

"More than ever, it's important to consider not only the car's ticket price but also its ongoing running and environmental costs," the Minister for Transport, Anthony Albanese, said.

From October, new cars will have to display labels telling people how much petrol they use and how much greenhouse gases they are likely to produce.