ADDIS ABABA, ETHIOPIA, DEC. 18 -- The Ethiopian government and Eritrean rebels today agreed to reopen the rebel-held port of Massawa, a move that could help ease the effects of a devastating drought in northern Ethiopia that has caused widespread hunger and raised fears of a famine like the one that killed a million people five years ago.

The accord was announced in Rome by the U.N. World Food Program (WFP) following separate negotiations with the government of President Mengistu Haile Mariam and the Eritrean People's Liberation Front (EPLF), which captured the port last February. The pact was welcomed by relief workers, who said Eritrea is poised on the brink of mass starvation and Massawa is the only route by which to send enough food to avert it.

"The reopening of the port is a major breakthrough for the provision of humanitarian food aid to people in Eritrea affected by drought and civil strife," said WFP Executive Director James Ingream in a statement from Rome. "All parties should be congratulated on their willingness to cooperate and compromise on what have been long and difficult negotiations."

The statement said the first WFP ship carrying food would leave for Massawa from Djibouti, Ethiopia's tiny neighbor in the Horn of Africa, early next month.

Although an earlier agreement to open the port was scuttled in July after the EPLF turned back a ship, observers said the two sides showed more genuine determination this time to resolve the issue, leading some to suggest that today's accord could become the first concrete step toward peace between the government and the rebels.

The Mengistu regime was characterized as the more flexible negotiator by officials familiar with the Massawa bargaining -- one of several factors in striking contrast to the government's slow and much-criticized response to the 1984-85 famine.

"The government of Ethiopia has bent over backward to make this possible," said an international aid official. Diplomats concurred, saying the government had relented in letting at least the first ship enter Massawa along a northern channel controlled by the rebels, as opposed to a more direct southern route that would pass by an archipelago of government-held islands.

Observers said the decision to resume food shipments via Massawa was as delicate and difficult for the government as for the rebels. In implementing the accord, both sides effectively will give recognition to the status quo in their long-running war.

"One of the reasons we're pushing Massawa so much is that once you agree to it, you have effectively started the peace process," said a U.S. official, whose government is trying to bring the two sides together. "You can't very well open up a peaceful front and then start bombing or shelling the convoys of food," the official said. The agreement is "a tough thing for the government to do, because it's admitting they can't retake Massawa. It's tough for the EPLF, because they have to admit they can't retake Asmara," the Eritrean capital, which is in government hands.

Ethiopian and international relief officials have said that anywhere from 4.3 million to 6 million people nationwide face severe food shortages and the risk of starvation. At least two-thirds of them reside in the parched and war-torn northern provinces of Eritrea and Tigray, where crop failures have reached proportions that many equate with those of 1984-85. Most of the remaining drought victims are concentrated in the provinces of Welo, Gonder and Harerge.

The food situation has been seen as especially bleak in Eritrea because reserves are believed to have run out after a second dismal harvest in a row and because of the effects of war and earlier droughts. The conflict also has shut down most industries in the province, which once was the country's economic heartland, robbing people of their ability to buy the food that nature does not always produce.

Although an emergency U.N. airlift to Asmara is now working around the clock and is expected to ferry in about 7,500 to 9,000 metric tons of food aid a month, Ethiopia's Relief and Rehabilitation Commission has estimated that Eritrea's needy require more than three times that amount. And although rebel-organized relief operations run from across the Sudanese border, carrying about 10,000 to 13,000 tons of food aid a month, the Eritreans still are far from getting the food they need

"The situation is getting worse every day," Yilma Kassaye, head of the government relief commission, said. "We are seeing the first clear warning signs . . . of a situation that could get very bad."

Relief officials have not yet seen mass migrations, slaughtering of cattle or abandoning of homes on the vast scale that characterized the 1984-85 famine. But in areas north of Asmara they report growing numbers of children with distended bellies and gaunt limbs, the signs of malnutrition.

Many peasants have fled to the capital, where they encounter severe shortages of food and water and exorbitant prices for staples. Asmara, under rebel siege, has regressed to the pre-motor age, with horse carts replacing cars for lack of fuel and electricity available only a few hours a day.

"The needy {in Eritrea} are now scraping the bottom of the barrel," said Timothy Painter, the WFP representative in Addis Abbaba. "Their recent harvest was a disaster and they've got a whole year ahead of them before they have another chance to get food of their own. They're at a very critical stage."

In the Harerge lowlands, cattle range through fields of drought-damaged sorghum, now of no use to humans. UNICEF workers in the area recently encountered a group of 150 people, heads of their families, who had walked 22 miles in search of food. The U.N. Food and Agriculture Organization, making its annual crop assessments, appealed last week for 1 million tons of emergency food to stave off famine in 1991, warning that "widespread loss of life is inevitable unless further emergency relief and logistic support for its distribution are mobilized."

Yet that report offered a glimmer of hope for Ethiopia: a record national crop this year of grains and pulses. Although grim predictions hold for many areas of the country, Ethiopia's prospects for feeding itself in the future appear better than at any time since the 1974 revolution.

This is largely due to a dramatic change in the government's attitude toward its chronic food problems. Unlike 1984-85, when authorities denied the extent of the famine, this year the government produced what has been regarded as its best and most comprehensive study of the country's food situation.

Addis Ababa also has negotiated with its rebel foes, as demonstrated by the Massawa pact and by a six-month-old agreement that allows food to pass through areas held by Tigrayan rebels. It also has liberalized farming policies, allowing peasants to cultivate their own land to a large degree and to sell at free-market prices -- key factors behind this year's bumper crops in areas where rainfall was adequate.

"These changes in economic policy have been very important for us and brought many surpluses," said Yilma of the Relief and Rehabilitation Commission. "But, we still have a long way to create a solid economic base that will create {security} for the peasants."

International relief officials agreed. "A one-year change in a 20-year trend of declining food production doesn't solve the enormous problems Ethiopia has in feeding itself," said Willard J. Pearson, USAID's representative in Ethiopia. "And yet if they can put together a few years of such progress, it is certainly possible for Ethiopia to eventually become agriculturally self-sufficient. . . . But only if there is peace."