Flight of the peso: what it will take to stem outflow of Latins' capital.

It was an embarrassing contradiction. There were the international financiers, visiting Uruguay's fashionable Punta del Este for the recent annual meeting of the Inter-American Development Bank. And there, scattered along that famous ''Gold Coast,'' they encountered wealthy Argentines from across the River Plate replete with their mansions, servants, and other luxuries.

Yet at the conference the financiers listened to pleas of poverty from Argentine officials trying to convince these visiting bankers and finance ministry officials that Argentina needed easier loan repayment terms. The contradiction cost the Argentines some sympathy, at least in their current negotiations over terms for a huge new loan from the International Monetary Fund (IMF).

If the international financiers had visited Miami and other cities in Florida , they would have seen more Latin American wealth invested in condominiums, office buildings, and similar properties. Local bankers could have told them about billions of dollars placed in savings deposits or other financial instruments.

All this is what economists call ''flight capital.'' It is money seeking sanctuary in the United States or other havens from political instability and poor economic management at home.

Huge amounts of money fled Latin America a few years back. The Bank for International Settlements in Basel, Switzerland, an institution serving central bankers of industrial countries, reckons that ''at least $50 billion'' left Latin America during 1978-82. Rimmer de Vries, chief international economist at Morgan Guaranty Trust Company in New York, says, ''It is probably a lot more than that.''

Indeed, the flight of capital was one of the key things prompting the debt crisis (50 to 75 percent responsible, says Mr. de Vries), which reached a critical point in August 1982 when Mexico announced a moratorium on servicing its international debts.

The departure of so much money meant that Latin American nations were having to borrow more money just to balance their international accounts. Today, their total debts come close to $350 billion.

Since 1982, however, the amount of money leaving Latin America has fallen off dramatically.

''The stream has slowed to a trickle,'' complains Gloria B. Kingsley, an agent with Miami's Fontainebleau Realty Inc. In fact, she goes on, the stream is , if anything, flowing mildly in the opposite direction now.

Faced with a strong dollar and sharply devalued domestic currencies, some Latin Americans are unable or unwilling to continue mortgage and maintenance payments. They have been selling their condominiums, depressing the Miami market. Prices on average are off at least 10 percent since 1981. On Brickell Avenue, a popular street for ''Latino'' investments in luxury condos, prices are off 20 to 25 percent in the past year.

Jack Birnholz, an international real estate consultant in Miami, sees the picture a shade differently. He detects signs of Latin American investors ''coming back into this country.'' He speaks of new activity on Florida's west coast, and in Texas, Arizona, California, and Colorado.

''Even though they (Latin American) face exchange controls, they are getting the funds out ... probably illegally,'' he says.

For instance, Mr. Birnholz says, he has just visited a 196-unit, luxury condo project in the Florida Keys aimed exclusively for sale to Latin American physicians. Apartments start at $275,000.

Right now, the international banking community is hoping for a sizable reverse flow of money back into Latin America. But the bankers anticipate that this will actually occur, in the short run, only in Mexico. Mexico is considered furthest along among the chief Latin American debtor nations in putting its economy and balance of payments into better shape. The other main debtors are Brazil, Argentina, Venezuela, Chile, and Bolivia.

But Mario Salamanca, an economist with Banco Nacional de Mexico, says, ''There doesn't seem to be a reversal in net terms.''

Considering the sums of Latin American capital placed abroad, even a modest flow reversal could do much to ease the debt-service burdens of debtor nations.

In Mexico, for instance, Morgan Guaranty figures that more than $25 billion left the country between between 1978 and 1982 - some $9 billion alone in the crisis year of 1982. The United States Federal Reserve estimates Mexican deposits in US banks at $10.2 billion. Mexico's total external debt is around $ 90 billion.

In Florida's Dade County alone there are an estimated $5 billion to $7 billion of bank deposits by Latin Americans, says J. Antonio Villamil, vice-president and chief international economist of Southeast Bank in Miami. That amount has been rising rapidly lately because Latins, for fear of political insecurity, have been shifting money out of offshore banks in the Bahamas, Panama, or the Cayman Islands to the ''international banking facilities'' of US banks in Miami.

''But this is basically a bookkeeping operation,'' Mr. Villamil says.

One of the goals of the IMF in attaching conditions to loans to Latin American nations has been to make the domestic economic scene attractive for local investors. The IMF wants to keep Latin money at home and attract flight capital back.

Thus a typical loan condition imposed by the IMF is a sizable devaluation. If a currency is overvalued, the domestic investor putting his money abroad not only can expect the normal return on that flight capital but stands an excellent chance of getting a bonus when the domestic currency is eventually devalued. If the currency is correctly valued or even undervalued, the risks for flight capital are greater.

For instance, the Mexican peso was devalued from 26 to the US dollar at the beginning of 1982 to an official rate of 187 to $1 today. But a dollar in international free markets has been getting as much as 230 pesos. Mr. Villamil suspects this may be one reason there was some renewal in capital flight from Mexico earlier this year. So-called ''errors and omissions'' in the Banco Nacional de Mexico's international-payments statements reached $1.054 billion in the first quarter, higher than any quarter last year. This payments statement item is usually considered one indicator of flight capital, which, by its nature (sometimes illegal), is not easily measured.

Another aim of the IMF is to get interest rates high enough to tempt capital to stay home.

In Mexico short-term rates are around 62 percent; inflation has been at about 53 percent annually. So the real rate of return is only 9 percent. US Treasury bills pay more than 10 percent; the inflation-adjusted rate of return would be 4 to 6 percent.

Mr. Salamanca in Mexico City describes current Mexican short-term rates as ''more or less attractive.'' Mr. Villamil in Miami wonders if the return is so low as to encourage capital flight, and thus speaks of how ''the US could help by improving its own economic policies so interest rates are not so high.'' He was referring to the huge US budget deficits, usually blamed for high interest rates and the strong dollar.

''It makes it very difficult for Latin American countries to attract capital back,'' he said.

Healthy growth rates also would help attract capital back to Latin America. But this is a chicken-and-egg problem: Getting capital back would strengthen growth, but stronger growth would tempt capital back.

The return of flight capital, says Henry N. Frothingham, vice-president in charge of Latin American operations at the Bank of Boston, ''is a vital component in the internal capital formation necessary to sustain growth, especially for private business.''

Henry C. Wallich, a member of the Federal Reserve Board in Washington, described the conditions needed for the return of capital to the Latin American nations as political and economic stability, realistic exchange rates, and a positive real rate of return on investment.

Apparently those conditions have not been met, as Latin capital is still flowing outward. ''Presumably the people that took the money out know more about their countries than other people,'' Mr. Wallich said.