CANBERRA, Australia -- Two-thirds of Australians oppose the country's newly implemented carbon tax, and the government that created it would suffer a crushing defeat if an election were held now, a poll released Monday said.

The poll published in Fairfax Media newspapers shows that support for the tax aimed at reducing greenhouse gas emissions is at its lowest level since Prime Minister Julia Gillard announced the measure in February 2011.

Almost 300 of Australia's biggest polluters will pay 23 Australian dollars ($24) per metric ton of carbon dioxide they emit under the tax, which took effect Sunday.

The poll by market researcher Nielsen found that 66 per cent of respondents oppose the tax and only 33 per cent support it. It also found that 58 per cent of respondents would vote for the opposition if an election were held now. National elections are due late next year.

Gillard said Monday that she expects many Australians will begin to realize that they are not financially worse off under the tax, and that coal will continue to the country's most lucrative export after iron ore.

"Now Australians get their own chance to judge, not based on what the politicians are telling them, but based on their own lives and their own experiences," she told reporters.

The government expects to raise about AU$9 billion a year from the tax. Most of that revenue will be used to give people with low incomes tax cuts and increased welfare benefits to compensate for higher prices and electricity bills.

Monday's poll found that 51 per cent of respondents believe they will be worse off financially under the tax, while only 5 per cent believed they would be better off. Another 37 per cent expected the tax would make no difference to them while the remainder were undecided.

"The government has completely failed to sell the policy and I think they've left voters more confused than informed," Nielsen director John Stirton said.

He said the ruling centre-left Labor Party has not been competitive in opinion polls since Gillard announced the tax, breaking an election pledge that such a tax would never be introduced by a government that she led. She agreed to the tax in a deal with the minor Greens party, whose support enables her party to form a minority government.

Australia is one of the world's worst greenhouse gas emitters per capita, due largely to its heavy reliance on abundant coal reserves for power generation.

Conservative opposition leader Tony Abbott has vowed to scrap the tax if he wins government, which all opinion polls agree is likely.

The poll was based on a random telephone survey of 1,400 voters nationwide from Thursday through Saturday last week. It has a 2.6 per cent margin of error.