At a meeting in the Republic of Korea, they agreed a shift of about 6 percent of the votes in the IMF towards some of the fast-growing developing countries.

Those nations will also have more seats on the IMF's Board, while Western Europe will lose two seats. But the US will retain the veto it has over key decisions.

Such decisions require an 85 percent vote - Washington holds 17 percent under the IMF's weighted voting system.

The ministers also agreed to refrain from competitive devaluations of their currencies and move towards more market-determined currency systems.

Much of the tension in the currency market is being blamed on the US and China, although it is not clear that either country will be restrained by the latest agreement.

The pressure has been on China to end its policy of holding the yuan down to maintain its competitiveness.

There was, however, no timetable for change in the devaluations agreement, so Beijing has kept to its long-held position that it will reform its currency policy gradually.