Nigeria, Indonesia and North Korea have the world's highest rates of deforestation while China and the United States, the top two greenhouse gas polluters, have the lowest, a global ranking released on Thursday shows.

Growing demand for food and biofuels, rising populations, poverty and corruption are driving deforestation in many developing countries, said risk analysis and mapping company Maplecroft, which compiled an index for 180 countries.

The company used the latest data from the UN's Food and Agriculture Organization to calculate changes in the extent of overall forest cover, and in primary and planted forests between the years 2005-2010.

Those at the top are ranked extreme risk.

Australia is ranked tenth and listed as high risk, while India, Vietnam and Spain are at the bottom, with low risk.

Brazil is ranked number 8.

Extreme risk countries are losing plant and animal species that help provide benefits such as clean air from forests, watersheds for rivers and mangroves that protect coastlines, services that help underpin economies.

“Deforestation can also hamper efforts for a country to reduce their carbon dioxide (CO2) emissions as forests play key role in mitigating global climate change through carbon sequestration,” Maplecroft analyst Arianna Granziera told Reuters in an email.

Forests soak up and lock away large amounts of CO2, helping act as a brake on climate change.

Yet deforestation is disrupting this cycle and is responsible for at least 10 per cent of mankind's annual greenhouse gas pollution.

The index comes days before the start of major UN-led climate talks in South Africa in which delegates are expected to discuss ways to try to curb emissions from the deforestation.

Indonesia is losing about 1 million hectares of forest a year.

That's about 13 times the size of Singapore, with palm oil expansion accounting for about 16 per cent of deforestation, Maplecroft said.

The government in May began a two-year moratorium on issuing new licences to clear primary forests and peat lands and will conduct regular satellite surveillance to monitor the ban.

Brazil's deforestation fell to 2.2 million ha annually between 2005-2010 but green groups worry changes to national forest protection laws awaiting Senate approval could ease restrictions on the amount of rainforest farmers can clear.

Green group WWF said on Wednesday approval of the revised laws could open up vast amounts of forest to agriculture and cattle ranching.

Nigeria, ranked first in the index, lost just over two million hectares of forest annually between 2005-2010 driven by agricultural expansion, logging and infrastructure development.

While China was the best performer because of aggressive protection laws and replanting schemes, it was driving deforestation in other countries, Granziera said.

“China's demand for wood is fuelling increasing imports, much of which comes from the USA and Canada, but illegal imports from Brazil, Cambodia and other developing countries have been reportedly increasing,” she said.