World Trade Organisation (WTO) chief Supachai Panitchpakdi has expressed confidence that global trade talks would meet a July deadline for a key deal.

"I am not thinking about any plan "B". There has to be an agreement... (and)... I am still confident that it can be done," he told Reuters in an interview.

The WTO director-general, who will be attending this week's conference of the United Nations' trade and development agency, Unctad, in Sao Paulo, Brazil, said planned talks between ministers on the fringes of that gathering could be crucial for the outcome of current negotiations in Geneva.

They would be "important, if not decisive" for what kind of agreement would be possible in agriculture, the most contentious area of trade reform despite accounting for only a tiny slice of global commerce.

WTO states are racing to complete outline deals, or frameworks in trade parlance, for a number of key areas of the Doha Round of free trade negotiations, in trouble almost from their launch in late 2001.

The collapse of a ministerial conference in Cancun, Mexico, last September almost derailed the negotiation, and the July deals aim to put trade liberalisation, which economists say could be worth $500 billion to the world economy, back on track.

Asked the price of failure, the quietly spoken former Thai premier paused: "I want to use the right words... It would really be inadvisable," he said finally.

After July, the United States will be distracted by November presidential elections and the European Union will also see sweeping change in its executive Commission.

But probably more importantly, all momentum for the talks, which were supposed to be concluded by the end of 2004, could be lost, leaving the timing of any resumption an open question. "I have said it could be years," Mr Supachai added.

From Sao Paulo, Mr Supachai said he hoped to see more from the G20 developing country alliance, led by Brazil, India and South Africa, on how far they could go on opening their own markets.

He applauded the alliance, whose defiance of the richer states contributed to the confrontational atmosphere in Cancun, saying it had since made positive proposals.

But he said he was looking for greater "specificity", or clarity from the G20 on market access for farm goods, one of the three so-called "pillars" of the agricultural negotiations along with domestic support and export subsidies.

"If there is no specificity, then things could get stalled," he said.

At the same time, he said views were converging over export subsidies, where the European Union opened the way to a deal by recently agreeing to discuss dates for an end.

Mr Supachai said there were signs others were ready to meet Brussels' demand for "parallelism", namely that the United States give similar commitments about its export credit schemes and that countries with state monopolies, known as state trading enterprises, such as Canada, put them on the table too.

On domestic support, he said the US, which along with the European Union is a lavish user of farm subsidies, had made it clear it was ready to "go far" in cutting them.

However, others still needed reassurance that Washington was not planning simply to shuffle subsidies out of one category into another, leaving their net impact little changed.

Mr Supachai said talks in Geneva on cotton, which some African producers wanted treated separately from the overall farm negotiations, were making headway. Africans say huge US subsidies to its farmers are driving them out of business.

"The good news is that we have made progress in Geneva on cotton," he said.

One crucial element was apparent US willingness to allow a specific mention of it - an exception to the rule - in any general accord on the slashing of farm subsidies.

But he warned a decision on whether to launch negotiations on how to standardise customs procedures and cut corruption, known as trade facilitation, was still not fully resolved.

Poor states, whose opposition to setting out new areas for negotiation helped bring about the Cancun debacle, still have doubts, particularly about the potential cost.

"We have converged... but I do not think that we can say that we have it wrapped up," he said.