Blanchett and Fraser were among 140 personalities and organizations who signed a petition distributed to federal lawmakers supporting the center-left government's plan to make polluters pay for every ton of carbon gas they produce in a bid to reduce the nation's greenhouse gas emissions.

The petition - whose signatories also include a Roman Catholic bishop and a Nobel Laureate scientist - is part of a $1 million national newspaper and television advertising campaign funded by environmental groups and unionists. Opinion polls show that both the tax and Labor are unpopular with voters.