NAMACATA, MOZAMBIQUE -- Attacks by right-wing guerrillas on humanitarian relief convoys have cut off more than 1 million subsistence farmers from emergency food supplies and have brought the country to the brink of widespread famine rivaling that of Ethiopia, according to foreign relief agencies here.

The destruction 12 days ago of this impoverished refugee village six miles east of the Zambezia provincial capital of Quelimane -- and hundreds more like it in central and northern provinces of Mozambique in the last several years -- also has brought the country close to economic collapse, senior government officials and western diplomats warned.

The attacks, and the looting and burning of fields at harvest time, have prevented as many as 2 million more Mozambican farmers from producing crops, resulting in severe food shortages directly affecting 6.5 million of the country's 14 million people, independent relief officials said.

Moreover, the growing number of attacks on trucks carrying emergency food to rural areas is forcing relief agencies to turn to costly airlifts, putting a further strain on assistance budgets.

The war being waged by the rebels of the Mozambique National Resistance, also called Renamo, has been condemned by the Reagan administration, which sees Mozambique's Marxist government as seeking to improve its ties to the West and possibly willing to abandon its socialist course.

The United States last year donated $10 million in economic aid to Maputo and $75 million in food assistance. To the consternation of some conservatives, Reagan, who met with Mozambican President Joaquim Chissano in October at the White House, has resisted a lobbying campaign to win U.S. backing for the rebels.

The attack here on Jan. 12, while barely noticed outside the province, was typical of the almost daily guerrilla raids that have plunged this former Portuguese colony into relentless agony.

Sneaking through the elephant grass in three groups and encircling the refugee camp before taking aim at its flimsy straw huts with AK47 automatic rifles, the guerrillas shattered the predawn stillness with their deadly fire.

The sleeping deslocados, or displaced, who had fled their own villages months earlier during similar attacks, shouted the alarm "Bandidos!" and ran in terror into the bush.

The platoon of 30 government troops protecting the camp fired a bazooka round, according to the villagers, and then also fled into the bush as the attackers methodically burned 37 thatched huts and a mud-brick community center.

After removing their own tattered clothes and dressing in looted clothing, the guerrillas took as much food and as many cooking utensils as they could carry, along with several villagers forced to serve as bearers, and vanished into the night.

Villagers said that before leaving, the attackers planted some land mines and left a photograph of Alfonso Dhlakama, 33, the Renamo leader.

Next to the photograph, they said, the guerrillas left a small mound of corn, apparently a warning that the peasants are expected to keep the rebels fed.

Half-starved by continuous drought and numbed by 10 years of brutal civil war, the refugees could be expected to be traumatized into speechlessness by the attack.

But standing amid the charred remains of their village, they spoke matter-of-factly about their ordeal, saying they would not bother to expend much energy to rebuild their crude shelters because they will only be burned down again.Forced to Leave Home

The destruction of villages such as Namacata has forced an estimated 1.8 million people to abandon their homes as Renamo continues to battle the government for dominance.

Visits to other remote villages in the northern provinces of Mozambique elicited similar stories of destruction, hunger and human misery from peasants so accustomed to violence that they accept it as a way of life.

The tour by several foreign correspondents traveling by bush plane and Land Rovers and on foot to normally inaccessible rural districts was arranged and conducted by the independent relief agency CARE International, which runs the largest food distribution program here.

CARE officials said they invited the correspondents in hopes of focusing public attention on an annual 800,000-ton food deficit in Mozambique that has led to a famine crisis rivaling the better-known plight of Ethiopia.

The misery of Mozambique has been exacerbated, CARE representatives and American diplomats in Maputo said, by rising guerrilla attacks on emergency food convoys to the famine areas. In the past three months alone, more than 400 people have died in ambushes on convoys, many of them within 30 miles of Maputo.

Since 1984, CARE officials said, 15 of its truck drivers and assistants have been killed in ambushes, 75 trucks destroyed or seriously damaged and 450 tons of food and relief supplies looted or destroyed by guerrillas. They said another 500 tons of commodities was stolen or destroyed in attacks on warehouses.

"In the last six months, every road or rail line out of Maputo has come under attack. It's a nightmare trying to get stuff out of Maputo," said CARE director David Neff, adding that Renamo's strategy appears to have shifted from concentrating on the Zambezia Valley to trying to isolate Maputo.

Because of logistical delays, the normal three-day truck turnaround time for deliveries from Maputo to the provincial capital of Inhambane has grown to seven days.

Moving food 180 miles from the provincial capital of Tete to Zumbo in western Tete Province requires a 500-mile, 10-day trip through Zimbabwe and Zambia and back into Mozambique because of the threat of Renamo ambushes.

Renamo's disruption of transportation by digging trenches across roads, planting land mines and blowing up rail lines and bridges has forced CARE, which has more trucks than the government, to turn increasingly to expensive airlifts, at a cost of $500 to $600 per ton of cargo.

The relief agency charters DC3s for the job, but a recent decision by the International Committee of the Red Cross to discontinue its airlifts because of Renamo threats to shoot down the planes has slowed the flow of emergency food, CARE officials said. War's Human Toll

Dozens of impromptu interviews in remote, war-torn areas put a human face on government statistics, which say that more than 100,000 have died in the last three years as a result of the war; that 610 were killed in two massacres alone last year; that 3.2 million displaced people require emergency food supplies, and that more than 500,000 have fled to refugee camps in neighboring countries, most of them to Malawi.

In Inhaminga, in Sofala Province, where peasants stream daily into resettlement camps, some wearing nothing but strips of tree bark for clothing, there was widespread evidence of famine.

Small children with distended abdomens and pencil-thin limbs characteristic of advanced malnutrition sat listlessly under trees in the scorching heat as their parents talked of going weeks without food before abandoning their outlying villages.

They told of months of being forced to work as slave laborers for Renamo guerrillas until they decided to risk escape.

Inhaminga has a permanent population of 300, but it has swelled to 7,110 because of the influx of refugees seeking food, many of them still foraging for caterpillars and cassava roots to eat while they wait for periodic airlifts of emergency food.

"The first day they arrive, always one or two of them die. More of them die on the road walking here," said CARE director Neff.

Throughout the camp there were freshly dug graves, marked with nothing but sticks thrust into the sandy soil.

A mile away, on a crude landing strip, three tons of Italian rice brought in by a DC3 cargo plane lay waiting for the local women to transport it to town. The women carry the 100-pound sacks on top of their heads because there is no gasoline for Inhaminga's only truck.

Those refugees who receive emergency food normally are given a total of 22 pounds of grain, 2.2 pounds of cooking oil and 2.2 pounds of beans per person each month. The food is distributed every 15 days. The ration is less than the required caloric intake, and CARE officials said that often refugees eat their half-monthly allotment in the first five days.

Mike Mispelaar, CARE operations chief in Mozambique, said that 35,000 tons of grain are needed each month to feed the hungry, but that the organization is currently receiving only 7,000 tons monthly.

In Vila de Sena, on the Zambezi River near the Malawi border, townspeople talked about the most recent attack, in which they said 11 people died and four were kidnaped by Renamo guerrillas last month. The once thriving railroad town also had been occupied by Renamo from September 1986 to March 1987, when government troops retook it.

Antonio Enoque, a local leader, said the bandidos came at night and threw a hand grenade into one house, killing seven persons inside, then opened fire on other houses as the residents and a contingent of Army troops fled across the river. Three days later, the soldiers counterattacked and drove the guerrillas out, he said.

Local residents said some of the guerrillas wore camouflage uniforms but most were dressed in civilian clothes and were carrying Soviet-designed AK47 rifles. They said most of the guerrillas spoke the Shona dialect common to Manica Province south of here, which is home to many of Renamo's military leaders, including its present chief, Dhlakama, who deserted the Mozambican Army in 1978.

Luis Jimo, who said he is about 50, told of being abducted by the guerrillas with his wife and five children and forced to march for four days to their bush camp with a 100-pound sack of rice on his back and no food to eat. He said another of his children was killed during the attack by a hand grenade blast.

"They said, 'Since you don't want to live with us, we have come to take you. If you run away, we will come back and kill you,' " Jimo said. After a few days, he said, he and most of his family escaped into the bush, leaving behind one child who was sleeping in another part of the guerrilla camp.

In other relocation camps and villages in Sofala and Manica provinces, residents told stories of similar abductions and attacks in which peasants were beaten and sometimes maimed by having their ears and noses cut off.

Sometimes, as in the case of the 25th of September Camp near Quelimane, entire towns of 1,000 or more people moved to protected relocation centers in order to escape constant Renamo attacks.

In some cases, the peasants said they were forced by government troops to move and were told that if they remained behind they would be regarded as supporters of Renamo.