ISTANBUL -- Finance ministers from developing countries said Monday that they should get more voting power at the World Bank, echoing calls for change at the International Monetary Fund.

Ministers from Russia, India, Indonesia, Brazil and Venezuela spoke at the annual meetings of the IMF and World Bank, held this year in Istanbul. They said the credibility of the bank, which assists developing countries, would erode unless countries have a voice consistent with their weight in the global economy.

The appeals follow a decision at a Pittsburgh meeting of the Group of 20 forum rich and developing countries that the G-20 would become the world's main economic decision-making forum, instead of the G-7 group of rich countries.

At that meeting, Group of 20 leaders agreed to redistribute at least 3 percent of voting power in the World Bank, and 5 percent in the IMF. The G-20 includes developing economic powerhouses such as China, India and Brazil.

"We must be aware that the World Bank's credibility and legitimacy could suffer without tangible and timely progress on the voice and participation reform in which we are currently engaged," said Jorge Giordani, Venezuela's minister of planning and development.

Aleksei Kudrin, Russia's finance minister, said Russia should have more say because its share in the world economy exceeds 3 percent, which is greater than its current voting power in the International Bank for Reconstruction and Development, a part of the World Bank.

The Washington-based World Bank loans money and makes grants to developing and poor countries to pay for investment in education, health care, infrastructure, agriculture and natural resource management.

The IMF fosters global monetary cooperation to facilitate international trade, and has bailed out a number of cash-strapped governments that ran into trouble during the ongoing world financial crisis.

In Istanbul last week, World Bank chief Robert Zoellick said he had called for an increase in the share of developing countries in the institution to 50 percent over time. The 3 percent increase proposed by the G-20 would create a 47 percent share for those countries, he said.

Pranab Mukherjee, finance minister of India, said a 6 percent shift in voting power was ideal.

"That would be truly transformational," he said. "The shift can happen at one go or in stages."

Guido Mantega, Brazil's finance minister, also applauded a 6 percent shift, but said the process should not be linked to changes in quotas at the IMF.

"They reflect largely the initial allocations and historical evolution, which the IMF is in the process of reviewing," he said.

The ministers spoke at a meeting of the World Bank's development committee, which sets policy.