British firm Maplecroft placed Australia's per capita output at 20.58 tons a year, some four percent higher than the United States and top of a list of 185 countries.

Canada, the Netherlands and Saudi Arabia rounded out the top five. China remains the world's biggest overall greenhouse gas polluter, followed by the United States.

Maplecroft added that China and India's per person carbon production came in at just 4.5 and 1.16 tons respectively, in sharp contrast to their big overall figures.

"Australia has about five times the per capita emissions of China for instance but China produces over 20 times the carbon emissions of Australia because China has such a huge population," University of Adelaide professor Barry Brook told public broadcaster ABC.

"So you can play around with these numbers all you want but ultimately what matters is the total global carbon budget," he said.

"And unless humanity as a whole can find solutions to that problem, then all of that petty bickering amongst nations about who's more or less responsible isn't really going to be very helpful."

The report was released ahead of a major UN summit in Copenhagen in December aiming to thrash out a new climate change treaty.

Australia, whose vast size and isolation make for high transport costs for goods and people, has committed to cutting greenhouse gas emissions by up to 25 percent by 2020 compared to 2000 levels.

However, emissions trading legislation was defeated in the Senate last month, leaving the target in doubt.