Argentina and the International Monetary Fund have reached agreement on an economic program designed to reduce the debtor nation's runaway inflation rate but are haggling over the size of the first installment of a $1.18 billion IMF loan, banking and government sources said yesterday.

The United States and other European and Latin American governments have agreed to make a temporary loan to Argentina to help it clear up the $1.2 billion in overdue interest it owes commercial bank lenders. The size of the temporary loan will be determined by how much the IMF will give Argentina in the first disbursement.

It will be months before the IMF actually lends Argentina any money because the international agency wants to be sure the nation actually implements some of the tough measures it agreed to take.

Only three months after Argentina reached agreement with the IMF last December the country was out of compliance with its economic program. A diplomat based in Buenos Aires said that the IMF staff felt it had been "burned" by Argentina the last time and wants to see the country take austerity measures before the IMF's executive board is asked to approve the pact and authorize disbursement of money.

But Argentina needs funds almost immediately -- both to unlock a $4.2 billion loan from its commercial bank lenders and to forestall U.S. banking regulators from declaring Argentine loans substantard. The debtor nation wants to pay as much interest as possible to its bank lenders to bring its loans current.

If the loans are current, bankers and Argentine officials believe, the U.S. regulators will not downgrade Argentine loans. A downgrading not only would be a blow to the nation's pride, but also would make it difficult for banks to justify lending the country more money. The country desperately needs cash to pay for imports and other international bills as well as its bank interest.

The Argentine government last night, in a terse communique, announced it had reached a "technical agreement" with the IMF, that it had cleared up all the questions with its commercial bank lenders and was actively talking with the United States, European countries and certain Latin American nations about the temporary bridge loan.

The bridge loan will be repaid when Argentina receives its first disbursement from the International Monetary Fund.

Argentine sources said the nation has agreed to reduce its budget deficit to an amount equal to 6 percent of the country's total economic production and to devalue its peso by 30 percent to make its exports more attractive and discourage domestic imports.

The government of Raul Alfonsin has proposed cutting federal spending by 12 percent this year and reducing the government's payroll by between 20,000 and 30,000 workers. The government said it would cut employes by attrition rather than layoffs.

Earlier this week the government raised energy prices by 30 percent to reduce its subsidy of energy products.

Argentina has $48 billion in foreign debts, $25 billion of which it owes to commercial banks. It owes the rest to other governments and to multinational agencies like the IMF, the World Bank and the Inter-American Development Bank.

In addition to agreeing to lend Argentina $4.2 billion in new money this year, the commercial banks also agreed to stretch out repayments of $13.4 billion in Argentine debts that have already come due or will in 1985.

The banks, however, have made the new loan agreement contingent upon the country complying with an IMF program. Whether the banks will be willing to disburse some of the new money to Argentina before the IMF's executive board formally approves a new agreement is unclear.

But some sources suggested that banks might be willing to disburse some funds if Argentina appears to be complying in good faith with the latest IMF program and if the IMF gives banks the nod to do so.

Last December, the IMF agreed to a 15-month program with Argentina in which it agreed to lend the country $1.4 billion. Argentina has nearly $1.2 billion left to draw and would like to get as much as $600 million of it in the first installment. The more it can get from the IMF, the more it can borrow from other countries to pay down the interest, and keep to a minimum its use of depleted foreign exchange reserves.