BUENOS AIRES, SEPT. 10 -- Rebounding from last weekend's election defeat, President Raul Alfonsin has rejected appeals for the quick dismissal of his economy minister but signaled a toughening of Argentina's foreign debt stance.

In his first public appearance since his ruling Radical Civic Union party lost congressional and gubernatorial races to the opposition Peronists, the Argentine leader announced the launching of a diplomatic offensive to freeze relatively low current interest rates on the country's $54 billion foreign debt "at historical levels." He told an audience of industrialists last night that Economy Minister Juan Sourrouille would lead the offensive along with Foreign Minister Dante Caputo.

This tacit endorsement of Sourrouille dampened speculation, which had been running high here, that Sourrouville would be dismissed and that economic policy would turn sharply to the left or the right.

Senior members of the Radical Civic Union confirmed that while some adjustments are still likely, they will be carried out by the government's existing economic team. Government sources, though, also left open the possibility of changes soon in other Cabinet posts.

Alfonsin and his aides seem to have concluded that Sunday's win by the pro-labor Peronists did not really reflect a repudiation of government plans to deregulate and privatize the economy. Rather, the loss is apparently being read as a sign of frustration with the government's failure to keep promises to revive the economy and keep inflation low.

"We have lost the elections, but the tree has not fallen," Alfonsin declared at a meeting of the Argentine Industrial Union. "Let nobody try to get wood from it ahead of time."

He did not mention a moratorium on debt payments, which the Peronists have demanded. In fact, he vowed to keep pressure on banks to grant new loans. But he lashed out bitterly at international financial institutions, accusing them of frustrating the growth of developing countries.

"We are not going to allow the World Bank to put aside the most important aims for which it was created -- namely, to attend to the problems of development, poverty and infrastructure," Alfonsin said.

"Nor are we going to allow the International Monetary Fund (IMF) to continue trying to apply ridiculous prescriptions that have nothing to do with the needs of people and that ignore the IMF's function of contributing to the solution of serious economic problems."

Neither Alfonsin's criticism of the multinational institutions nor his campaign to freeze interest rates were new. But the force and bluntness with which both were expressed and the formal announcement of a diplomatic offensive had the apparent aim of relieving domestic pressure for some action on the debt front.

"Alfonsin has decided to reaffirm his policy, giving it more force," said economist Javier Gonzalez Fraga. "But for domestic political reasons, he must also harden his foreign debt stance."

Alfonsin fiercely defended his economic program against harsh criticism delivered in his presence by Eduardo de la Fuente, head of the industrialists' association, who complained last night of a lack of clear rules for investment. The Argentine president said his administration has tried to make the economy more competitive by granting special business credits, promoting exports, drafting regional development plans and starting to sell off state-owned companies.

He blamed the lack of progress so far on, among other things, the foreign debt, a drop in prices for Argentine exports and the sheer difficulty of reversing a process of decline that began decades ago.

But many economic analysts here say Alfonsin is also partly to blame. He unwittingly undercut public confidence in his own program with the decision earlier this year to name Carlos Alderete, leader of the electrical workers' union, as minister of labor. Alderete's departure from the Cabinet is now widely expected.

The appointment had represented an attempt by Alfonsin's Radical Union advisers to forge an alliance with the so-called Group of 15, a large segment of Argentina's powerful labor union movement. The political maneuver was supposed to facilitate wage pacts, foster agreement on new labor legislation and co-opt some of the Peronist opposition.

Instead, analysts say, the move clouded the government's economic policy. The minister of labor ended up quarreling openly with the minister of economy.

Against this background, large wage hikes were approved. The deficit grew to 6.5 percent of national output by mid-year, three points above target. Monthly inflation soared into double digits in July and reached 13.7 percent last month.

As confidence in the government's economic management fell, the flight of Argentine australs into U.S. dollars quickened, causing the black market exchange rate to shoot more than 40 percent ahead of the official rate.