African countries at the International Monetary Fund have spoken out against proposals to give non-African poor countries a bigger say at the IMF.
Most of the world's poorest countries are in Africa
The IMF is due next month to discuss a package that would raise the profile of China, Mexico, South Korea and Turkey.
African IMF delegates say this would mean a delay in proposals to expand the role played by the world's poorest countries, most of them African.
They called on the UK and other countries to block the proposals.
UK Chancellor Gordon Brown, who chairs the IMF's key international finance and monetary committee, has previously backed calls for a greater African voice in the IMF.
Analysts say the African bloc would need only the support of the UK and one other rich country to force a change in the proposed reform plan, drawn up by by IMF managing director Rodrigo de Rato.
The proposal will be discussed at IMF's annual conference in Singapore in September.