Canada ranks among the top five countries that are the most effective in preventing companies from bribing, according to an annual survey.

But Switzerland topped the ranking of the Bribe Payers Index 2006 by the anti-corruption group Transparency International, which lists 30 of the world's leading exporting countries.

On a scale from 10 for no corruption, to 1 for rampant corruption, the highest score went to Switzerland with 7.81.

Sweden (7.62), Australia (7.59), Austria (7.50) and Canada (7.46) followed.

The U.K. ranked sixth (7.39), while the United States finished ninth, scoring 7.22. 

For the top five worst, India ranked at the bottom (4.62), followed by China (4.94), Russia (5.16), Turkey (5.23) and Taiwan (5.41)

"In the case of China and other emerging export powers, efforts to strengthen domestic anti-corruption activities have failed to extend abroad," the report said.

Although companies from the wealthiest countries were generally ranked in the top half of the index, the report noted that they still routinely pay bribes.

David Nussbaum, chief executive of Transparency International, said governments are still not doing enough to clamp down on bribery.

"The enforcement record on international anti-bribery laws makes for short and disheartening reading," he said in a statement.

"Bribing companies are actively undermining the best efforts of governments in developing nations to improve governance, and thereby driving the vicious cycle of poverty,"  said Transparency International chair Huguette Labelle.

More than 11,000 business people in 125 countries were polled for the index.