Alan Garcia, the overwhelming victor in Peru's first-round presidential election Sunday, said today that his government would bypass negotiations with the International Monetary Fund on its foreign debt and would promote joint action by Latin American countries on seeking new terms for outstanding commercial bank loans.

Garcia's comments on economic policy suggested that his government would adopt the most radical stance with the IMF and international banks yet taken by a major South American debtor and could presage an open confrontation with American banks.

Garcia, 35, the leader of the center-left APRA party, said the IMF's economic agreements with Latin American countries, the basis for management of foreign-debt problems, were "absurd" and involved "the colonial importation of concepts" by developing countries.

"It is not true that these types of measures are adequate for our economies," he said. Peru he said would seek to "pass over the [International Monetary] Fund so as to address our creditors directly."

In a press conference for foreign journalists, Garcia also sharply criticized the Reagan administration for "deformed concepts about Latin America" and praised Nicaragua's Sandinista government as "the progressive affirmation of democracy in Central America." He said his government would follow a "nonaligned" and "Third World" foreign policy that would stress the development of regional initiatives for treating the foreign debt and relations with the United States.

The statements came as vote calculations from Sunday's national election continued to show Garcia's total as just under 50 percent, more than double the nearest challenger but short of the majority needed to avoid a runoff.

Garcia, already acknowledged as the de facto president-elect by some political leaders, said he still hoped that his final vote count would reach 50 percent but that he would not object to a runoff with Marxist candidate Alfonso Barrantes.

"We will go to the second round to reaffirm the popular triumph," he said. "I want the people to ratify their first decision."

The commercial banks that have hundreds of billions of dollars in outstanding loans to Latin American countries have required that the debtor countries reach agreement with the IMF on economic programs as a condition for extending the terms of existing loans and providing any fresh funds.

Brazil and Argentina, which account for nearly $150 billion in outstanding loans, are currently trying to reach new agreements with the IMF.

If Peru did not accept an IMF program, it could provoke a confrontation with its creditors leading to the suspension of all credit to the country or even a formal default on its outstanding loans, financial sources here said. Such an action by Peru would be closely watched in Argentina and Brazil.

Peru's foreign debt stands at $13 billion and the country is nearly $300 million behind in interest payments to commercial banks.

Its last agreement with the IMF, linked to a tentative debt rescheduling plan with banks, was suspended last year after President Fernando Belaunde Terry's government failed to meet targets for reduction of spending and missed several interest payments.

Garcia maintained that the system of case-by-case renegotiation of Latin American debts through the IMF had not worked. "Because of our bad political formation, every one of our countries began a bilateral treatment of the foreign debt," he said. IMF policies, he said, were "incoherent" because they had been "inherited" from developed counties. The IMF has been used by the industrialized West, Garcia added, to force open markets in developing countries for exports.

"We need to go back to the concept of a new world economic order," Garcia said. "We have to reshape the game. Now only the debtors are paying the cost of the world crisis. This debt is an absurd promise of future payment."

"Latin America has to give a common answer," he said. "One country by itself cannot pay its debt. Only together will we be able to win better conditions in order to pay."

Garcia said the Reagan administration erred by "seeing Latin America through Central America . . . , which is a minor problem" compared with the economic difficulties of South America.

He said that the Nicaraguan revolution was "a very important democratic advance . . . behind which you don't have to see the hand of the Soviet Union, as do some gentlemen of the State Department."

Garcia acknowledged that there might be limitations on some rights in Nicaragua. But, he said, "you can't demand that from night to day, after decades of dictatorship, that democratic norms be followed in their entirety."