With the public wary of the plan and the opposition labeling it “a great big new tax on everything,” resource giants Rio Tinto and Woodside Petroleum called for strong protection from the new cost.

Climate Change Minister Greg Combet said details of compensation for industry were still being considered, and industry would be consulted on final details, but he said fewer than 1,000 companies would have to pay a carbon price.

“A carbon price is paid by the large organizations in our economy on every ton of pollution that they emit. There’s somewhat less than 1,000 entities that are likely to have a liability to pay a carbon price,” Combet said.

The number of companies liable to pay for emissions is similar to the number covered by the government’s former carbon trade plan, which was twice defeated in parliament and which offered free permits for up to 95 percent of emissions for firms exposed to overseas export competition.

Global miner Rio Tinto and Woodside, Australia’s largest oil and gas producer, are among Australia’s biggest carbon polluters, with combined emissions of almost 16 million tons.

Rio Tinto said the government must offer more generous compensation than under the former carbon scheme, while Woodside, said it should be exempt completely.

“Woodside believes the company’s trade-exposed exports should be exempt from any price on carbon, given the absence of an international agreement on pricing greenhouse gas emissions,” it said.

Rio Tinto said compensation proposed in 2009 was no longer reasonable for exporting industries, due to the lack of an international agreement to cut emissions.

“Businesses unable to pass a carbon price through to customers, which is most businesses competing in international markets, would simply have to absorb it,” said David Peever, Rio’s Australian managing director.

“Depending on the magnitude of the carbon price, this may be manageable when market conditions are favorable and margins are healthy. But when the cycle turns down, it will inevitably be disastrous,” Peever wrote in the Australian newspaper.

Gillard, whose predecessor Kevin Rudd was dumped by her ruling Labour Party last year after two failed attempts to address climate change, said polluters would pay a yet-to-be-determined fixed price, then move to a market-based system within five years.

The plan has put Gillard’s one-seat minority government under intense political pressure, with the majority opposition conservatives promising to reject it and warning consumers it will lead to higher electricity and living costs.

Underscoring the political risks, an Essential Media poll on Monday showed almost one in two Australians — or 48 percent — opposed the carbon price plan, with overall support for Labor slipping a point to 47 percent.

Only 35 percent of voters backed Gillard’s scheme, and 59 percent of respondents believed she had broken an election promise not to immediately pursue a carbon price after last year’s dead-heat election.

But in a rebuff to Rio Tinto and Woodside, most people were also opposed to compensation for heavy emitters, with 44 percent opposed to any buffer for trade exposed industries and a massive 68 percent opposed to help for power companies.

In contrast, 70 percent wanted compensation for householders and small business, the poll showed, while 47 percent of poll respondents wanted action on climate change as soon as possible, compared to 24 percent who wanted to delay action.

The Australian Greens, who help support Labor in the lower house and have a strong voice in the upper house, said the claims of Rio and other “big polluters” should be rejected by the government.

“We should be looking at the real world and when it comes to compensation, it shouldn’t be claims by these big corporations,” Party leader Bob Brown told local television.

Brown said compensation claims by emissions-heavy industries should be assessed by an independent arbiter or review process, to ensure corporates did not use their political influence to escape costs and leave taxpayers to make up the shortfall.

Rio has estimated the company’s annual carbon tax bill would be about A$154 million if the tax was set at A$20 a ton for every ton of carbon pollution.

Rio’s export operations would have faced an additional A$3 billion cost over 10 years from a carbon emissions trade scheme proposed in 2009 and which offered almost A$50 billion in compensation to industry and mining over the first decade.

Combet said he expected Australia’s new scheme would be internationally compatible once it moved on from the fixed price, in three to five years, and said there was considerable international momentum to cut global emissions.