The G-20, which comprises developed countries and the largest emerging economies, said problems faced by African cotton producers reflect distortions in global trade of agricultural goods.

"The plight of the African cotton producing countries and of other cotton producers in the developing world is evidence of the distortions in agriculture that we are committed to eliminate," the G-20 said in a statement;

"The G-20 ministers emphasise the need for a firm commitment to be made at Hong Kong to address the issue of cotton ambitiously."

The WTO meeting in Hong Kong, which opens later Tuesday, is tasked with keeping on track the faltering four-year-old Doha Round meant to tear down global trade barriers and spur growth in the world's poorest nations.

The key issue is farm trade, mainly the system of European and US subsidies which they say they will only surrender in exchange for a deal opening up markets in the developed world to their industrial goods and services.