UPDATE 1-Emerging nations want IMF bond plan revamped-Brazil

(Adds quotes from Brazil's minister, background, byline)

By Walter Brandimarte

WASHINGTON, April 23 (Reuters) - Brazil and other emerging economies are willing to provide additional financing to the International Monetary Fund but they are still not happy with the capitalization mechanism proposed by the institution, Finance Minister Guido Mantega said on Thursday.

The IMF is working on a plan to issue bonds to emerging countries that have offered to capitalize the institution, but the preliminary proposal presented by the board of the fund "still does not satisfy our demands," Mantega told reporters in Washington, where he was attending the IMF/World Bank meetings.

"We still have to improve this instrument," he said, adding that emerging countries such as Brazil and China will not make additional contributions to the fund while the new mechanism is not ready.

The minister stressed that Brazil would still make good on its pledge to contribute with as much as $4.5 billion to become a member of the fund's financial transaction plan, or the mechanism through which the IMF finances its loan operations.

But the additional pledge of $10 billion made by the country during a G20 meeting earlier this month would depend on the definition of that mechanism.

The G20 agreed to boost the IMF firepower earlier this month through the so-called new agreement to borrow, or NAB, an emergency facility that allows member countries to provide credit to the fund in case of severe crisis.

But Mantega said emerging countries are not happy about how the NAB was structured because it reflects the imbalances of current IMF voting power, which is dominated by rich nations.

He also called on the IMF to speed up a plan to issue $250 billion in special drawing rights to member countries, saying that would provide liquidity for nations to fight the global crisis. (Reporting by Walter Brandimarte; editing by Carol Bishopric)