Although Third World countries achieved a sharp increase in exports to the United States last year, the underlying protectionist trend throughout the industrial world "is clearly upward," Jacques de Larosiere, managing director of the International Monetary Fund, said this morning in a Stockholm speech.

According to the text of his address -- released here last night by the IMF -- "protectionism is clouding the medium-term prospects for an orderly resolution of the debt problems and for restoring a satisfactory pace of development in the Third World."

De Larosiere said that products subject to one kind of trade restriction or other "accounted for about 30 percent of total consumption of manufactured goods in the United States and the European Community in 1983 -- up from 20 percent in 1980."

He reminded an audience of Swedish business executives that leaders of the rich nations had pledged numerous times at summit sessions to roll back trade restrictions imposed during the recent recession. But "action has not followed," making it difficult for debtor nations to extend their recovery through larger exports, he said.

"However determined the efforts of the debtor countries, their success also depends on the industrial countries achieving sustained growth and keeping their markets open," de Larosiere said.

Because a new round of multilateral trade negotiations will take some time to put in place, he called on the larger nations -- including the United States -- to "honor their commitments to halt protectionism." He cited, especially, devices such as countertrade, quotas and "voluntary restraints."

De Larosiere noted that some of the poorer countries have been making progress in getting rid of their own trade restrictions.

De Larosiere said imports for a group of 34 countries getting help from the IMF in January would rise nearly 10 percent in dollar terms and 7 percent in volume this year, continuing a recovery in imports that began in 1984. For the same group, economic growth was "moderately good" last year and there should be further gains of almost 4 percent this year, he said.