GENEVA -- GATT chief Peter Sutherland warned Thursday that the United States would strike a "mortal blow" to the new world trade pact if the U.S. Congress, shaken by mid-term elections, failed to ratify the deal by the end of the year.


He told a news conference a collapse of the treaty, negotiated over seven years in the GATT's Uruguay Round and due to go into force in Jan. 1 next year, would sow alarm on world markets and undermine global economic recovery.


"It is inconceivable that a country that has so much to gain from the Round ... could strike what would be a mortal blow to the (world trading) system by putting off the debate," Sutherland declared.


He was voicing fears among other countries in the 124-member GATT, the General Agreement on Tariffs and Trade, that sweeping Republican gains in the elections could lead to postponement of a key Congress vote on the pact on Dec. 3.


Trade diplomats said these fears have been fed by a call Wednesday from Senate Republican leader Bob Dole for more explanation from President Bill Clinton on the treaty -- concluded in December last year and signed in Morocco in April.


Sutherland, who played a vital role in steering the long Round negotiations to a triumphant finale, said he still expected passage of the treaty when the lame duck Congress meets from Nov. 29 to Dec. 3 to approve it.


But he said postponement would also mean that the new World Trade Organization (WTO) to absorb GATT and supervise the freer trading system created by the accord could not come into being at the start of 1995 as planned -- if ever.


GATT officials and trade diplomats fear that if the Republicans decide to table their own bill on the treaty to the new Congress rather than approve the administration's own package, it would be picked apart in endless debate.


They believe a new bill could run foul of a decision by Clinton that after this year trade accords would not be pushed through as a package in the so-called "fast track" approach.


Postponement "is not an option ... It is imperative that the agreement be implemented," Sutherland said.


The report, prepared by GATT analysts, said tariff cuts and lowering of barriers for industrial goods under the accord would alone put an extra $510 billion annually into the world economy by the year 2005.


Of this, the United States itself would be reaping a bonus of $122.4 billion with an export boost of 21.7 percent, according to the report.


Sutherland said he feared that if there were delay in the U.S., there would be a chain reaction among other top traders -- the European Union, Japan and Canada -- who also still have to ratify.


This would mean, he said, that not only would the world lose the benefits of the agreement but the GATT system would begin to crumble.