By Sam Cage and Jonathan Lynn

DAVOS, Switzerland (Reuters) - Rich and poor countries aim to meet around Easter to try to seal a long- elusive global trade deal before U.S. President George W. Bush leaves office, ministers said on Saturday.

A trade deal would inject much-needed confidence into a troubled world economy, and help ward off protectionist trends, ministers said.

"We have a window of necessity which is also a window of opportunity," Brazil's Foreign Minister Celso Amorim said.

Ministers representing the United States, the European Union, emerging market leaders Brazil and India, and a dozen other trading countries met World Trade Organisation chief Pascal Lamy in the Swiss mountain resort of Davos on Saturday to discuss the chances of getting a breakthrough in the Doha round.

"We've agreed that, if the round is going to be done successfully, it needs to be done this year. It needs to be done on President Bush's watch," EU Trade Commissioner Peter Mandelson told reporters.

"But if we're going to do a deal in that timescale, then that points to a necessary breakthrough, which only ministers can do, at Easter or thereabouts," he said.

Easter falls this year towards the end of March.

Swiss Economy Minister Doris Leuthard, who hosted Saturday's lunch for ministers, said the idea of a meeting around Easter was proposed by Lamy and supported by all those attending.

"We are much nearer to 'nearly there' than last year," Lamy said.

NUMBERS

The Doha round of talks, launched in late 2001 to boost the world economy and fight poverty, has lurched from crisis to crisis for years over differences among rich and poor countries over cutting farm and industrial tariffs and subsidies.

Agriculture accounts for only about 8 percent of world trade but is the key to any deal because of its importance for developing countries.

The chairman of the WTO agriculture talks aims to issue a revised negotiating text around the end of this month, and that will be followed by one for market access in industrial goods.

Australian Trade Minister Simon Crean told Reuters that the extent to which the revised papers narrowed gaps between the WTO's 151 members would determine the timing of a meeting of ministers to bed down an outline deal.

Brazil's Foreign Minister Celso Amorim said the next two to three months would now be crucial for the negotiations.

But he said a deal had to give developing countries the same flexibility in opening up their fledgling industries to competition that rich nations were now being offered in politically sensitive farm sectors.

"Differences are not so big any more in terms of numbers, sometimes they are bigger politically than in economic terms," Amorim told reporters.

U.S. COMMITTED

U.S. Trade Representative Susan Schwab said Washington was determined to see a deal by the end of the year.

"There's no meeting scheduled but I think that clearly there's a sense of momentum," Schwab told Reuters. "The United States is fully committed to seeing a successful completion of the Doha round in 2008."

Indian Trade Minister Kamal Nath, emphasising any deal had to benefit developing countries, said a meeting of ministers was needed around Easter after further talks at the WTO in Geneva.

"We've agreed that the momentum, the intent and the will have never been more to bring this round to a close," he told Reuters.

But Egypt's Trade Minister Rachid Mohamed Rachid injected a dose of scepticism. He said some countries questioned whether major players such as the United States, China and India really wanted a deal, and called for the negotiations to be recast to reflect changed circumstances, such as record food prices.

"The Doha round is raising fewer and fewer expectations because every year we keep saying if we don't do it the whole world will collapse, and every year we don't do it and the whole world gets better," Rachid told Reuters.

For full coverage, blogs and TV from Davos see: http://uk.reuters.com/news/globalcoverage/worldeconomicforum2008