Prime Minister Julia Gillard has defended the $23-a-tonne starting price for carbon emissions, after the price in Europe's carbon market fell to between $10 and $13 in recent months.
The opposition and some business groups say the $23 price to be imposed on around 500 businesses from July 2012 is much higher than international prices and will disadvantage Australian industry.
The Business Council of Australia said it would push for amendments to the legislation, which passed parliament on Tuesday, if the Treasury modelling on the price proved wrong.
Ms Gillard on Wednesday told a Carbon Expo in Melbourne, where she was greeted with lengthy applause, the European price volatility was not unexpected given the general uncertainty in the European economy.
"We worked with Treasury to model what the right starting price was to give us the smoothest possible lift to where we would need to be for that international linking price (in 2015)," she said.
"I do want Australian businesses in our emissions trading scheme to be paying a price which is the world price. That is a very important part of the scheme."
The European price was around $23 in June, before the region's sovereign debt crisis starting spooking markets.
Federal opposition climate spokesman Greg Hunt said the coalition remained determined to repeal the legislation if it won government because of its adverse impact on the community and industry, without doing anything to address emissions.
"There would be an overwhelming mood in the community to repeal the tax," Mr Hunt told ABC radio.
"The whole thing could be done and dusted within six months."
However, asked by a business executive at the forum whether she believed the coalition would honour its repeal commitment, the prime minister said: "My prediction would be we are seeing the maximum drama right now, but it will abate over time".
Anti-carbon tax protesters are expected to rally in Canberra next week when US President Barack Obama addresses a joint sitting of parliament.
The opposition also has called on the government to rule out more spending on advertising the carbon pricing scheme, on top of around $24 million already spent.
"This is naked, partisan political advertising," Mr Hunt said.
One of the government's backers, independent MP Tony Windsor, said that rather than advertising, there should be more focus on getting clean energy projects started.
"Word of mouth will carry the message. Political spin tends not to," he said.
Assistant Treasurer Bill Shorten said any advertising would be aimed at providing accurate information about the scheme and its benefits.
"What we'll be doing is talking about how the new scheme is going to actually work," he said.
Ms Gillard said the carbon price would have only a third of the price impact of the GST, while helping households and industry cut "nine out of every 10 tonnes of the carbon pollution we would otherwise have released into our atmosphere".
