Department of Agriculture officials warned yesterday of sharp cutbacks in the nation's food-stamp program next year unless quick relief comes from Congress.

Carol Tucker Foreman, assistant secretary for food and consumer services, said about $2 billion more will be needed this fiscal year to continue assistance at current levels.

Although any USDA decisions on cutbacks are several months away, Foreman said the congressional calendar, with its month recess for Christmas, has put new pressure on the program.

"There is not a hostile attitude in Congress," she said, "but what really concerns us is the calendar and the potential for running out of money."

She and Robert Greenstein, administrator of the Food and Nutrition Service, said that continuing inflation in food prices and growing participation in the stamp program had created the money problem.

Congress appropriated $6.2 billion for this fiscal year, which will end next Oct. 1. USDA estimates it will need $8.3 billion to provide benefits at present levels for the full fiscal year.

Part of USDA's problem stems from congressional action that put a ceiling on food-stamp spending for this fiscal year.

The Senate has passed legislation removing the ceiling for this year and fiscal 1981, but the House Argiculture Committee has just begun to deal with a bill to lift the ceiling for this year.

An aide to Chairman Thomas S. Foley (D-Wash.) said the House committee hopes to complete action on its bill this week. A House floor vote and conference with the Senate then would be required.

Foreman said action on removal of the ceiling and separate appropriations action to provide more funds for food stamps would be necessary by mid-February to avert major changes in the program. "If by Feb. 15, we know that Congress is not going to act or increase the money, we would have to tell the states to cut back benefits by April 1," Foreman said.

If the unlikely decision were made simply to cut off the program during the last four months of the fiscal year, she said, USDA also would have to begin notifying the states by April 1.

Nineteen million persons, about 60 percent of them either very young or very old, participate in the food-stamp program. Revisions directed by Congress in 1977 cut about a half-million persons off the rolls, but overall participation has gone up by about 3 million, Foreman said.