The United States has asked the U.N. Disaster Relief Organization to coordinate and oversee all emergency relief in Ethiopia, where 3 million people are affected by food shortages, it was announced yesterday.

M. Peter McPherson, administrator of the Agency for International Development, said he asked UNDRO to be the lead agency as part of an effort to ensure that U.S. assistance is being utilized effectively.

The request follows announcement this week of a $3 million allotment for food aid to Ethiopia next year. U.N. officials have estimated that 50 to 100 children are dying daily in that country as a result of food shortages caused by drought and civil war.

AID and relief organizations agree that the main problem in Ethiopia now is not a shortage of food but transportation difficulties caused by the destruction of bridges and a lack of trucks.

Ken Hackett, Africa regional director of Catholic Relief Services, recently returned from Ethiopia, where he said the famine situation is "very severe . . . . The magnitude of the problem is enormous."

"The reason why it will continue to grow is basically the transport problem," he said. "Food won't be brought in, seed won't get to the right areas and it's raining right now. If they miss this planting, the situation isn't going to stop in November but is going to continue on into next year."

The relief agencies want to purchase trucks for use in Ethiopia but they say that AID will only give money for leasing trucks, apparently out of fear that they might be used by the Soviet-aligned Ethiopian regime. Asking UNDRO to coordinate emergency work, relief officials said yesterday, could make it easier for AID to be more active.

"The situation in Ethiopia," McPherson told UNDRO, "calls for a lead agency on the ground to coordinate and oversee the operations of the many donors. If additional emergency food and/or transport assistance will be needed, the ability to manage, monitor and assure accountability will be major considerations."