New Zealand is the world's least corrupt nation

Australia is among the least corrupt country in the Group of 20 industrialised nations, while New Zealand was ranked first, according to a new survey.

Transparency International, a global body leading the fight against corruption, said its annual league tables showed that New Zealand stood at top of the global list overall as the least corrupt in the world, according to AAP report on Thursday.

Last year, Australia's trans-Tasman neighbour was ranked joint first alongwith Denmark and Singapore, which now stand at second and fifth respectively.

Australia remains in joint eighth position with Switzerland.

TI's Corruption Perceptions Index scores 183 countries and territories from zero (highly corrupt) to 10 (very clean) based on data from 17 surveys that look at factors such as enforcement of anti-corruption

laws, access to information and conflicts of interest.

Two-thirds of ranked countries scored less than five.

New Zealand scored 9.5 compared while Australia achieved 8.8 this year.

North Korea and Somalia both scored just one point and ranked at the end of the scale.

"This year we have seen corruption on protesters banners, be they rich or poor," AAP quoted TI chief Huguette Labelle as saying while releasing the report in Berlin.

"Whether in a Europe hit by debt crisis or an Arab world starting a new political era, leaders must heed the demands for better government.

"Australia's number one trading partner China was ranked 75th in the world with a score of 3.6, while its number-two trading destination Japan was 14th with a score of 8.0", the report said.