"There is a serious risk that the multilateral system will be undermined," said Gonzalo Fanjul, head of agricultural research for the anti-poverty group.
He said the WTO needs to use a ministerial meeting in Hong Kong next month to regain credibility after a session in Cancun, Mexico, in 2001 collapsed in acrimony, paralyzing the global trade body for months.
The WTO's 148 nations now are well behind schedule for a new deal to lower import barriers and to reduce agricultural subsidies. Breaking a deadlock over subsidies in the heavily protected farming sectors of Europe and some other developed countries has become a key focus of the talks.
The U.S. and the European Union have offered to make deep cuts in their farm subsidies, but Oxfam says they do nothing to improve the fortunes of poor nations.