BUENOS AIRES, JAN. 11 -- Mounting concern about Argentina's ability to meet its debt payments is prompting government officials here to sound out the United States about further financial support, according to bankers and economists.

A team of senior Argentine officials, including Treasury Secretary Mario Brodersohn, central bank president Jose Luis Machinea and Economy Minister Juan Sourrouille, plans to fly to Washington tonight, and will meet with U.S. Treasury Secretary James A. Baker III, Michel Camdessus, managing director of the International Monetary Fund, and Federal Reserve officials.

If they negotiate a multimillion-dollar emergency loan, as bankers and press reports here predict, it will be the third time in the last year that Argentina has turned to the United States for rescue funds. The United States lent Argentina $500 million last February and again in October.

Lower world prices for farm exports and higher-than-planned imports of oil, petrochemicals and semifinished products have resulted in a deterioration of Argentina's foreign exchange reserves. Although the government forecast a trade surplus of $2.5 billion last year, the trade account was in the black by only $588 million through September, and bankers estimate that the full-year surplus was actually $700 million.

For this year, government officials have projected a trade surplus of $2.75 billion, and bankers already are skeptical.

A new $500 million bridge loan from the United States would enable Argentina to meet interest payments in the absence of financing from other creditors, including the International Monetary Fund and more than 300 foreign banks.

Central bank director Daniel Marx insisted that Argentina had not yet decided whether to ask for a bridge loan from the United States.

According to both Marx and bankers, the Argentines themselves are not yet clear on how much they will need -- and will not know until an IMF team here finishes its work checking Argentina's 1987 economic performance. The five-man IMF mission arrived here last week to review the government's compliance with targets set in return for a $1.425 billion standby loan signed a year ago.

Bankers believe the government badly overshot the target it gave the IMF for the 1987 budget deficit. This was supposed to equal 4 percent of gross domestic product, but the real figure, bankers say, probably came closer to 7 percent or more.

On the trade surplus, Marx conceded the projected 1988 figure of $2.75 billion is "unlikely," although he said he thought Argentina might double last year's disappointing surplus of an estimated 700 million.

Argentina is due to pay $4.7 billion in interest on its $52 billion foreign debt this year. The big question is where the funds will come from.

Apart from the trade surplus, which will still be very low by historical standards even if it doubles, there is concern about Argentina's official reserves. The government averted a debt crisis last year by drawing a total of $1.7 billion from reserves. But reserves available this year are thought to have dropped to around $500 million.

These figures persuade government insiders and bankers alike that Argentina is going to need big loans this year from overseas creditors -- and that ultimately means overcoming problems with the IMF and the banks.