Federal Reserve Board Chairman Paul A. Volcker yesterday urged commercial banks to increase lending to Latin American debtor nations to stimulate economic growth in those countries, and said that it would require a relatively small boost in lending.

Volcker said that the U.S. government's plan to encourage growth in the economies of Latin American debtor nations would involve only a 2.5 percent to 3 percent yearly increase in bank lending to the region.

That is a far slower rate than the rate at which banks boosted their loans to Latin America in the late 1970s and early 1980s.

Volcker said that the $20 billion U.S. Treasury Secretary James A. Baker III wants banks to lend over the next three years is about what Mexico alone borrowed from commercial banks in 1981.

The Federal Reserve chairman told reporters that "everybody will be better off" if banks cooperate with the debt plan unveiled by Baker earlier this month during the annual meetings of the World Bank and International Monetary Fund in Seoul.

At a press conference following an address to the annual convention of the American Bankers Association, Volcker said it was up to banks whether to increase their lending to developing nations on a bank-by-bank basis or as a group. Since the onset of the so-called Latin American debt crisis three years ago, banks have negotiated collectively with individual debtor nations.

Volcker also met with executives from more than 100 of the nation's biggest banks yesterday to outline the Baker proposal and to urge them to join in the plan to resuscitate Latin American economies. Although many of the debtor nations have resumed economic growth -- after devastating recessions in 1982, 1983 and early 1984 -- their income levels are no higher than they were a decade ago.

The Baker proposal is a recognition that Latin American nations are chafing under the austerity programs they have imposed during the last three years. Those measures represent an effort by the debtor nations to husband dollars to pay their more than $350 billion in foreign debts, about $230 billion of which is owed to commercial banks.

The plan not only calls for a $20 billion increase in commercial bank lending over the next three years, but also for a $9 billion increase in lending from multinational institutions such as the World Bank and the Inter-American Development Bank. Many of the loans from the official institutions would be tied directly to domestic economic changes that would require the debtor nations to dispose of some of their money-losing, inefficient state companies and open up their economies to more internal and external competition.

"Happily, that is the direction in which new leaders in Latin America -- democratically elected leaders -- have repeatedly said they want to take," Volcker said in remarks prepared for delivery to the bankers group.

He told the bankers that more growth cannot be achieved in Latin America without a "moderate" increase in lending from commercial banks, but said that the banks and the countries have a "common interest in sustainable growth -- growth necessary to meet the legitimate aspirations of the borrowers and growth not unduly dependent on external finance."

He said the growth would "progressively lighten both the heavy debt burdens of the borrowers, relative to the size of their economies, and the exposure of the lenders, relative to their assets and capital."

Volcker said that debtor nations that take steps to reform their economies and to continue to pay their debts "can legitimately ask that they have some assurance" of increased loans from commercial banks and international institutions as long as the countries "do their part of the job."