LUANDA, ANGOLA -- In a surprisingly candid disclosure of widespread urban hunger and governmental failure to induce farmers to sell surplus food, the Marxist government here has prepared its largest-ever request for international emergency assistance.

The request, to be presented to donors late this month, says that about a million people, half of Angola's urban population, face "acute shortages of staple foods, a situation which may deteriorate into near famine conditions . . . from September onwards."

To feed people in cities, as well as an estimated 690,000 displaced people in rural areas, the government is seeking 245,000 tons of food and other emergency aid worth $116 million.

A report on the food crisis, prepared by the government in coopertion with the United Nations, says the flow of food from farm to city has been "virtually halted" due to lack of transport, disruptions of communications and "the near absence of marketing structures."

Despite a "possible improved maize {corn} harvest" this year, the report says the government does not have "the necessary consumer goods to trade this surplus production from the peasants."

Angolan farmers refuse to sell their food for Angolan currency, which is nearly worthless. Instead, according to agriculture specialists here, farmers insist on bartering for such goods as clothing, hoes and soap that the government does not have the capacity to manufacture, the money to import or the means to transport.

A primary cause of this "severe emergency," according to the report, is the country's 12-year-old civil war with the National Union for the Total Independence of Angola (UNITA), a rebel movement supported by the governments of South Africa and the United States.

Another cause of the food shortage is last year's collapse of world oil prices. Oil revenue amounts to 90 percent of Angola's foreign exchange earnings. As the country's farm economy has collapsed in the 12 years since independence, the government has come to rely on oil earnings to buy imported food for city people. Reduced oil income has cut in half the country's ability to feed these people, the report says.

"The emergency situation in Angola has characteristic features of its own," the report says. "These stem from a combination of the prolonged destabilization campaign and military aggression waged by South Africa, of the resultant disruption of the rural economy, the transport sector and government services."

A senior Angolan official said here this week that the emergency aid request, by detailing the worsening human cost of the war, is intended to embarrass the United States into ending its support of UNITA.

This year, for the second year in a row, the U.S. government is sending at least $15 million in military hardware to the prowestern rebel group.

The Reagan administration has said that the military equipment, provided out of the budget of the Central Intelligence Agency, is intended to pressure the Angolan government to negotiate with UNITA and to force the withdrawal of an estimated 37,000 Cuban troops from the country.

Angolan Vice Minister for Foreign Affairs Vanencio de Moura, who has dealt directly with the State Department in stalled negotiations over the Cuban presence here, said this week that U.S. support of UNITA has strengthened, rather than weakened, the government's intention to keep Cuban troops in the country.

He said that aid to UNITA is "clear interference in our internal affairs," and that it is prolonging the war while causing increased civilian casualties.

De Moura added, however, that as part of Angola's new emergency appeal, the Luanda government had "no problem accepting" bilateral famine aid from the U.S. government.

"Whatever help should come from the people of the United States will be welcome as long as it is not subject to preconditions," de Moura said.

In the past year, the U.S. Agency for International Development provided 12,000 tons of fortified grits, vegetable oil and dried skim milk for distribution in Angola by the U.N. Children's Fund (UNICEF).

The U.S. government recently notified UNICEF officials here that it is willing to increase its contribution to more than 24,000 tons in the coming year.

"It is weird, but one has to be understanding of international geopolitics," said Babourcar N'Jie, resident representative here for UNICEF.

"It has not ceased to blow my mind that on one hand we are getting more and more victims of this war, and on the other hand we are getting more and more food from the United States for these victims."

U.S. food aid for victims of U.S.-supported rebels is only one of the ironies of American involvement in Angola. Cuban troops guard American oil company installations in the Cabinda region. American consumers buy about two-thirds of Angola's oil, supplying the government with foreign exchange it uses to buy Soviet weapons to supply troops fighting U.S.-assisted UNITA guerrillas.

For the most part, the government's new emergency report ignores strategic and military issues. Instead, it details the growing social cost of the war.

It says that the number of women and children who have lost limbs because of antipersonnel mines dug into fields and roads now exceeds 10,000. There is widespread agreement among western development specialists here that UNITA plants the mines to terrorize the local population and make it appear as though the government does not control the security situation.

The number of displaced persons, especially in Angola's central plateau region where UNITA is most active, has risen by about 100,000 people in the past six months, the report says.

"The situation has taken a new dimension of urgency due to the increasingly debilitated condition of displaced persons and the steady deterioration in the nutritional status of the severely affected population," the report says.

The child death rate, which UNICEF says is the highest in the world, may worsen because of the "recent resurgence of highly infectious diarrheal and water-borne diseases," the report says. An outbreak of cholera in Luanda this spring killed several hundred people. The report said that up to 45 percent of Angola's children suffer from some kind of malnutrition.

According to UNICEF, about 80 percent of those displaced by the war are women and children.

Besides showing the high human cost of the war, the emergency report is a frank admission by the Angolan government that it has all but ignored social services in the country.

"Core technical and managerial manpower . . . is principally allocated by the government to national defense," the report says. "Consequently there has been a continuous reduction of key administrative, technical and managerial personnel, especially at the provincial level, in all the government's social and technical services."

The report appeals to international donors to fill the vacuum caused by the government's preoccupation with war. It asks for money for rebuilding and staffing health centers, for vaccinating cattle, digging wells, providing displaced people with farm implements and supplying trucks to deliver all the requested aid.

Over the next year, the report calls for the delivery of more than 200,000 tons of food to ports in the country.

Senior U.N. officials here said the logistical capacity of the government to deliver such a large amount of relief food has improved in the past year.

"If food delivery is staggered in phases, if it is properly planned and delivered to the right port, the government should be able to organize its delivery," said Jean-Pierre Gerney, deputy resident representative here for the U.N. development agency.

Other U.N. officials, noting that deliveries of food are impossible in most of the country without military escorts, said they doubt that such a large amount of food can be delivered in time to help hungry people.

"The problem right now is not lack of donated food in the country," said a U.N. logistics expert. "The problem is getting the military to organize convoys for delivering it.

"We have enough food for four convoys a month to the center of the country, but the government seems incapable of organizing more than two convoys a month."

Asked about the military escorts, Jose Antonio Martins, the senior Angolan official responsible for coordinating the government's relief effort, said Angola would find a way to deal with the problem.

"When the food comes," he said, "solutions will be found to organize the convoys."