European Union Trade Commissioner Peter Mandelson has warned he will not offer new reforms on agricultural subsidies during world trade talks in Hong Kong.
The EU says it has already offered significant subsidy reductions
Speaking as delegates gathered for the World Trade Organization (WTO) summit, Mr Mandelson said a deal on immediate subsidy cuts was "not possible".
The world's poorest countries want the WTO to reach a fair trade agreement that would see farm subsidies reduced.
A deal on agriculture remains the main stumbling block at the six-day meeting.
The WTO Ministerial Conference, which officially starts on Tuesday, is supposed to rubber-stamp a new global free trade agreement.
Mr Mandelson said the 149 WTO member countries at the so-called Doha round of global trade talks should focus on agreeing formulas for cutting farm subsidies and tariffs next year.
Security for the event, which starts on Tuesday, is already tight
"There's simply too little on the table to negotiate about in Hong Kong," he said at a pre-summit press conference on Monday.
Amid an atmosphere of low expectations at the talks, the EU and other WTO members called for planned trade measures designed to help 32 of the organisation's least developed countries to be implemented.
BBC News economics reporter Steve Schifferes said the move was widely seen as an attempt to shift the agenda of the trade talks to an area where agreement was more likely to be reached.
Mr Mandelson on Sunday held an evening meeting with trade chiefs from five key counterparts the US, Japan, Australia, India and Brazil.
Both the US and developing countries claim the EU is not prepared to make sufficient cuts to the support it gives its own farmers or reduce tariffs on imported food.
US trade representative Rob Portman called on the EU to make further progress on agriculture subsidies at the summit.
"The key to development is market access, agriculture access is the top challenge and we think that we need to make more progress here," Mr Portman said on Monday.
"The gains of expanding trade will not occur in developing countries or the Europe unless the EU is willing to agree to a formulae that meets the Doha requirements."
The EU has said its final offer of a 46% cut in farm tariffs remains a significant reduction.
Brussels also says it has an obligation to protect farmers in former European colonies, who receive preferential trading with Europe.
At the same time, a number of other developing countries also criticise the US and Japan for not sufficiently opening up their markets.
"Now it is clear that unless a miracle occurs - and I'm not even sure what kind of miracle - we won't have a final deal ... in Hong Kong," Brazilian foreign minister Celso Amorim said on Monday.
India's commerce minister Kamal Nath urged the EU and the US to end farm subsidies and open up their markets to developing countries.
"The WTO is not about free trade, it is about fair trade, and fair trade means a level-playing field," he said.
With security preparations high, authorities expect up to 10,000 protesters opposed to the WTO and a global free trade deal to hit the streets of Hong Kong during the summit.
In all, 6,000 delegates are expected to attend the WTO talks, together with 2,000 representatives from non-governmental organisations and 3,000 journalists.