Opposition emissions trading spokesman Andrew Robb said the Government should not press ahead with plans to start the scheme in 2010.

The meltdown had to be taken into account. ''It's going to discourage other countries around the world, they're going to look at other priorities, and it's going to put pressure on the speed with which they tackle climate change,'' he said.

The Government should also wait for the result of world climate talks in Copenhagen in late 2009.

''This scheme will be finalised before the Government's had an opportunity to know the outcome of next year's Copenhagen summit, before they've had an opportunity to know what the new US President will do,'' he said.

Mr Robb reiterated the Opposition's policy that emissions trading should start in ''2012 at the latest''.

The Government's greenhouse adviser Professor Ross Garnaut called on Tuesday for emission trading to start in 2010, saying the financial meltdown was short-term and no excuse for a delay.

But Mr Robb said Professor Garnaut had not backed up his call.

''He said that, but in my view he didn't substantiate it.''

Mr Robb also took aim at Professor Garnaut for his comments about businesses crying wolf over the costs of emissions trading.

Various businesses and business groups, including LNG supplier Woodside, Visy recycling and the Business Council of Australia, warned about the ramifications of emissions trading.

They predict factory closures, job losses and business moving offshore, and want more exemptions and compensation for businesses.

Professor Garnaut did not think the warnings were genuine. ''Why would you expect public policy advice in the national interest, from the chief executive of a business who's responsible to his board and shareholders for maximising the profit of that business?'' he said on Tuesday.

Mr Robb bristled at Professor Garnaut's comments.

''That is implying that they're telling fibs: I don't accept that,'' he said.

In Professor Garnaut's final report to Government, he said it would be a good idea if people ate more kangaroo and less beef and lamb, because kangaroo was a greenhouse-friendly meat.

Professor Garnaut's report pointed to modelling that showed cattle and sheep numbers could be cut drastically, while kangaroos increased to 240 million.

This would save emissions and be more profitable under a high carbon price.

But the Opposition labelled the proposal a ''sick joke''. AAP