The United States is giving more food to this famine-stricken country than any other nation in the world, but it is not giving Ethiopia any seeds to grow its own food.

The U.S. Agency for International Development is accepting bids to build grain-bagging machines at Ethiopian ports, but it will have to tear them out as soon as U.S. grain is unloaded. Every day the United States feeds hundreds of thousands of malnourished peasants here free of charge, but it does not allow them to participate in a food-for-work program that would build roads in this vast, road-scarce nation.

The official reason for this seemingly illogical aid policy is a U.S. law that prevents the government from giving anything other than "humanitarian" aid to countries that have nationalized American property and have not made a "good faith" effort to pay for it. Ten years ago, after the Ethiopian revolution and the emergence here of a Marxist military government, the new rulers seized American property, including some private homes, a few airplanes and an Addis Ababa-based factory of the Kalamazoo Spice Co. Of those seizures, U.S. officials here say, about $30 million of outstanding claims by 20 individuals remain.

The language of the law forces the United States to make distinctions in foreign aid between what is "humanitarian" and legal, and what is "developmental" and illegal.

"The law forces us to make a distinction between putting food in starving babies' mouths and building warehouses here that could store that food," a U.S. diplomat said this week. There is, however, more to the denial of U.S. development aid to Ethiopia than the relatively paltry sum of $30 million and a part of the Foreign Assistance Act called the Hickenlooper Amendment. The law is named after its sponsor, the late senator Bourke Hickenlooper, a conservative Republican from Iowa. It was passed in 1962 in response to the nationalization of U.S. property in a province of Brazil.

Behind the denial of development aid that could help Ethiopia recover from a famine that is now threatening the lives of 7 million people there also lies mutual hostility between the rigidly communist People's Republic of Mengistu Haile Mariam and the strongly anticommunist administration of President Reagan.

Marxist Ethiopia dismissed the United States as its economic and military patron in 1974 and turned to the Soviet Union. With the easy-credit sale of about $2.5 billion in military equipment, the Soviets helped Mengistu in wars against Eritrean rebels in the north and Somali invaders from the south.

But in recent months, as this country has appealed to the world for help in fighting a famine that the United Nations this week estimated has claimed 300,000 lives in the past nine months, the United States has been more willing or able to give food than the Soviets.

According to western diplomats here and members of a House delegation that visited Ethiopia this week, the infusion of U.S. food has opened a window that may allow for friendlier U.S.-Ethiopian relations and resolution of what is referred to here as the "Hickenlooper question."

"I feel that the government of Ethiopia is close to coming to an agreement with us on Hickenlooper," Rep. Mickey Leland (D-Tex.), chairman of the House Select Committee on Hunger, said this week after meeting with Mengistu and other Ethiopian officials. "All they have to do is make a good-faith effort."

For its part, the government says it has been making a good-faith effort for the past three years. It has established a compensation commission, which says it has settled about 80 percent of all outstanding claims by individuals and companies around the world.

"We have offered what we think is fair and most have accepted it," said Getahun Terefe Kassu, head of the claims commission. By far the largest U.S. claim is by the Kalamazoo Spice Co. of Michigan. Its factory here was nationalized, and Getahun said the company is asking for $20 million in compensation. The Ethiopian government refuses to pay that much, and settlement is not likely soon, Getahun said.

What makes this dispute over an amendment to the U.S. Foreign Assistance Act important, according to famine-relief officials here, is that it is getting in the way of using American money for long-term development of farming, roads and land reclamation that could end Ethiopia's chronic reliance on emergency food. According to U.S. officials here, the Hickenlooper amendment does not permit American food to be paid to impoverished but able-bodied Ethiopians for work in constructing roads and other permanent improvements to the countryside. Because of the amendment, U.S. food can only be donated, it cannot be earned.

Some famine-relief officials here say this interpretation is wrongheaded, needlessly pushing Ethiopian peasants into dependency.

"We can gets lots of food from the U.S. government," said Rhonda Sarnoff, associate director for public health with Catholic Relief Services, which is distributing food for about 700,000 destitute Ethiopians. "But we can't use that food to get people to build things that would help them solve some of their own problems."

Members of Congress here this week said they are going to try to resolve Ethiopia's problem by asking their House colleagues, who have constituents with claims against Ethiopia, to help push these people toward a quick settlement with the government here. Leland said he will ask Rep. Howard E. Wolpe (D-Mich.), chairman of the House subcommittee on Africa, to urge the Kalamazoo Spice Co. to agree to a prompt settlement.

Some critics here accuse the U.S. government of using the Hickenlooper amendment as an excuse to keep at arm's length from a pro- Soviet government. These critics, officials in international development agencies and private relief organizations, argue that deciding what constitutes a "good faith" effort for compensation is subjective and that Washington could resolve Ethiopia's problem whenever it wants.

In the meantime, both U.S. government and private famine-relief officials here are attempting, as one diplomat said, "to see how far Hickenlooper can be stretched."