Lamy warned that negotiators currently steering WTO farm trade discussions in Geneva could not make headway unless the EU and US made fresh concessions.

"There remains a need for movement by the big players," he told a meeting of African Union (AU) trade ministers in the Kenyan capital, Nairobi.

"More needs to be done and it is for the US to accept big cuts in agriculture subsidies," Lamy said.

"For the EU, Japan and others, they should accept what the US will have to accept in terms of subsidies plus real cuts in agricultural tariffs."

"Not that what is on the table is nothing, but it is insufficient to reach an agreement," Lamy said, referring to US and EU proposals offered ahead of an April 30 deadline to reach a framework deal on a comprehensive pact.

"It is absolutely important these heavyweights ... help us make steps foward in regard to modalities," he said. "We now need figures."

African nations have been at the forefront of efforts by developing countries to try to force the US and EU to drop agricultural subsidies as part of WTO talks aimed at tearing down barriers in global trade.

They argue the payments put African farmers at a huge disadvantage in the global marketplace. But they face resistance from EU and US officials, who are demanding greater access for their industrial and service sector goods.