Actor Michael Caton has accused Barnaby Joyce of playing "dirty pool" in his attack on actress Cate Blanchett over her participation in a carbon pricing ad campaign.

Both Caton and Blanchett appear in the new We Say Yes campaign, which calls for a price on carbon.

The advertisements are funded by a coalition of unions and green groups and come as Prime Minister Julia Gillard reportedly ordered her ministers to step up attempts to sell the Government's proposed carbon tax scheme.

Yesterday, Senator Joyce, the Nationals Senate leader, attacked Blanchett's role in the ads, saying that as a highly paid actor she needed to understand how the less well-off would be affected by the tax.

"It's very easy for people who have a good wage to suggest that we engage in a gesture which will have no effect, but the people who really pay the price are the ones who can't afford the fundamentals of life right now," he said.

But Caton says just because people are financially successful, it does not mean they cannot be passionate about a cause.

"It goes with the turf - if you're going to do something like this, you know that with 60 per cent of the population against the carbon tax, you're going to cop flak,' he said.

"And you've just got to be prepared for that.

"At the same time, the attacks on Cate I think are very dirty pool. It's basically saying that because you're rich you can't be passionate about something."

He said people should not be barred from making political statements just because they are wealthy.

"If that's the case, what is Malcolm Turnbull doing in politics? What is Kevin Rudd doing? His wife is one of the richest women in Australia," he said.

"I think that criteria is very unfair and below the belt."

The chairman of the Climate Institute, which is among the 11 groups which have paid for the campaign, has rejected Senator Joyce's criticism.

"I think she as an individual has as much right to make a comment as anyone else does," Mark Wooton said.

"A lot of the people making comments have a lot less credibility than she does. She actually did a training program about climate and she has a strong background in that area. So I think there's some stuff going on that people are a bit unfair."

Opposition climate spokesman Greg Hunt says Blanchett is "perfectly entitled" to make her point.

"The acting community is perfectly entitled to make their own campaign statements funded by the unions," he said.

"It would be helpful if they acknowledged the fact that Australian families will pay higher electricity prices, higher gas prices, higher grocery prices and higher petrol prices."

Opposition Leader Tony Abbott says the Government should be asking the public for support by holding an election on it.

"People are perfectly entitled to their view, but the view of celebrities accounts for no more than the view of the Australian public, and that's what the Prime Minister should be seeking," he said.

Backing for price

Climate Change Minister Greg Combet says there is a lot of support among business leaders for a carbon price, despite a major business group continuing to argue against one.

The Business Council of Australia and the Australian Industry Group are advocating a starting price of $10 per tonne, but the Australian Chamber of Commerce and Industry says that is still unaffordable.

Mr Combet says most business leaders support the Government's market-based mechanism for pricing carbon.

"Well, the chamber has had that view, but when you look also at the Business Council of Australia and the Australian Industry Group, a letter by 15 energy companies that is published today, there is a lot of support for carbon pricing," he told AM.

"Everyone knows, I think, broadly through the business community in particular, that using a market mechanism in the way that we've described is the least-cost, most-efficient way of achieving the reductions in emissions across our economy.

"You have got major business organisations in the form of the BCA and the IAG saying yes to carbon pricing, yes to a market mechanism to achieve it, because of the economic efficiency of that approach."

Tony Windsor, one of the key independent MPs being wooed by the Government in its bid to win support for the carbon pricing scheme, says a price of $10 per tonne is akin to doing nothing.

But he says he does not yet know how high the price should be.

"The $10 issue is a do-nothing issue," he said.

"If you had $10 on it you wouldn't bother doing anything, because all it would do is just rotate some money around the community with no gain in terms of environmental gain."

Dagger in the heart

Opposition climate spokesman Greg Hunt says the call for a $10 per tonne price means that business groups have put a dagger in the heart of the proposed carbon tax.

Mr Hunt says the business groups were not asked if they supported a carbon price.

Actually the question was, 'If you had to do it this way, how would you do it?'," he said.

"It's not the response the Government wanted, it's a massive vote of no confidence in the Government's model, with express, clear and absolute words, rejecting the Government's approach."

But former Liberal leader John Hewson, who is among 140 people who have signed a joint statement calling for a carbon price, says it is inevitable the business community will have to respond to the challenge of climate change.

"I actually believe Kevin Rudd was right that this is the moral imperative of this century," he said.

"I also think it's the greatest economic, political and social challenge of this century. It's far more important than any of the current politicians and players, and of their children and grandchildren, and it's something that needs to be dealt with effectively by public debate and proper policy.

"And you won't get that in a political contest in the 24-hour media cycle."

Others to put their name to the statement include actor Rebecca Gibney, author Tim Winton, artist Ken Done, rugby player David Pocock, Nobel Prize-winning scientist Peter Doherty and former prime minister Malcolm Fraser.