Opinion polls show that the carbon tax is already deeply unpopular among Australians. But Prime Minister Julia Gillard maintains it is essential to achieving her 2020 target of slashing greenhouses gas emissions to 5 per cent below 2000 levels.
Companies and local governments that annually produce more than 25,000 metric tons (28,000 tons) of carbon dioxide, or the equivalent in other carbon gases, must pay a tax of 23 Australian dollars ($23) for every metric ton of carbon dioxide they produce starting July 1.
BHP Billiton, the world's biggest miner, and Macquarie Generation, one of Australia's largest power generators, are on the list of carbon taxpayers, as are local governments that operate methane-emitting landfills.
The agricultural industry, Australia's third worst carbon polluter, is exempt because of difficulties in measuring emissions on farms.
Climate Change Minister Greg Combet said the number of carbon taxpayers could change in the months ahead as businesses either increase or decrease emissions.
Australia is one of the world's worst greenhouse polluters on a per capita basis due to its heavy reliance on abundant reserves of cheap coal for electricity generation.