The OECD has estimated that about $11 trillion, more than 10 times the amount committed by G-20 leaders to revive the world economy, is held in tax havens, even as it released the black list of non-cooperative nations.

Estimates of the value of assets held in tax havens range from $1.7 trillion to $11.5 trillion, the Organisation for Economic Cooperation and Development (OECD) said while naming Malaysia, the Philippines, Uruguay and Costa Rica as countries that have not agreed to implement international tax standards.

Mauritius, the country from where large amounts of investments are routed to India, figures among the nations that have substantially implemented tax standards.

Among the countries that have committed themselves to the internationally agreed tax standards but have not yet implemented them are Singapore, Switzerland, Bahamas, Bermuda, British Virgin Islands, and Cayman islands.

The OECD, which is a grouping of developed nations, released the list of blacklisted countries soon after the G-20 leaders announced a plan impose sanctions against tax havens.

"This is the start of the end because country after country is now signing up to the principles that have been set forward internationally. The principle is that you got to be prepared to exchange information about tax," UK Prime Minister Gorden Brown told reporters after the summit.