By Mark John

BRUSSELS, Jan 23 (Reuters) Trade ministers meeting in the Swiss resort of Davos this week could send out a signal that they are ready for a full relaunch of stalled global free trade talks, WTO chief Pascal Lamy said on Tuesday.

Although the Swiss-hosted session on Saturday would not get down to negotiations, it could provide a springboard for resuming the 5-year-old talks which were suspended by the Geneva-based World Trade Organisation (WTO) last July.

''I think that there might be, depending on their will, a signal of a full scale activity,'' Lamy told journalists.

The WTO's Doha round, launched in 2001 in the aftermath of the Sept. 11 attacks to boost the world economy and help lift millions out of poverty, was halted by divisions between major trading powers, notably over reforming world farm trade.

A flurry of bilateral meetings between key trade ministers in recent weeks and a resumption of technical level discussions in Geneva have raised hopes that the liberalisation negotiations could soon formally resume, but differences remain deep.

''We have started this year in a much more positive mood, not least because in the meantime the big bosses ... have had time to reflect on the big picture,'' Lamy said.

The former European Union trade commissioner said that what had already been agreed during the years of negotiations was already far more than had been achieved in the last global trade negotiation -- the Uruguay Round -- which was concluded in 1994.

''(It) is of an order of magnitude of three times versus the previous negotiation,'' he said.

Even on agriculture, where the European Union and other rich food importers and the United States are under pressure to come up with deeper tariff and subsidy cuts, current offers were worth two to three times that which was agreed last time.

On industrial tariffs, there was also the potential for much bigger cuts than in the past, and the same went for services, he said, referring to two key areas where big developing countries such as Brazil and India are being pressed for concessions.

Both EU trade chief Peter Mandelson and his U.S. counterpart Susan Schwab, who will be amongst the some 25 ministers in Davos, have said that progress has been made recently.

But the U.S. Trade Representative warned in an interview with Reuters on Monday that a breakthrough may be ''weeks away''.

However, time is not on the negotiators' side because the U.S.

administration needed major advances in the Doha round in order to be able to persuade Congress to renew the government's trade negotiating powers that lapse in June, Lamy said.

Without the powers, which limit Congressional intervention to a take-it-or-leave-it vote at the end, negotiating complex trade deals becomes all but impossible.

''The window of opportunity is rather small. It is in the order of magnitude of (the northern hemisphere) springtime,'' Lamy said.

He reiterated that he would be prepared to step in with proposals of his own for a deal if the Doha talks were ever on the point of becoming the first global trade round to fail.

REUTERS SBA PM1530