Amine and Kamel Mneimne were still waiting patiently this morning outside their old apartment building at 44 Farshoukh Street in central West Beirut.

For four days now, they have been standing there silently watching a huge bulldozer clear away the mountains of rubble where a three-story building once housed their families.

The two brothers, wearing gauze masks over the nose and mouth to shield them from the stench, are engaged in a grim task. They are looking for the remains of their wives, children and relatives still buried beneath the rubble. So far, 72 persons have been dug out, all dead, and 12 others are missing and presumed dead.

Figures seem guesses at best, but Lebanese police said yesterday that 9,583 persons had been killed and 16,608 others wounded since the start of Israeli air raids on the country 12 days ago.

The Mneimnes' building, which six families once shared, had been bursting with relatives and friends, who had come there from riskier quarters of the city to seek refuge from the intensive Israeli bombing of the city.

Instead, it became a tomb when an Israeli bomb fell five minutes after the cease-fire between Syria and Israel at noon last Friday and scored a direct hit, collapsing the building in a heap of cement, bricks and twisted steel.

Kamel Mneimne, a musician, is still hoping to recover the bodies of his wife, four children, one brother and one sister from the ruins. As he stood today dry-eyed and seemingly resigned to the loss, Kamel lamented, "We are all Lebanese. We are all Lebanese. Why us?"

The Mneimnes, however, do not believe the bombing was deliberate. They said they thought the Israeli pilot had dropped the bomb while trying to escape heavy antiaircraft fire coming from below. One of them remarked, as if in consolation, that he even had heard an apology broadcast over the Voice of Israel radio after the extent of the catastrophic "mistake" became known in Tel Aviv. Still, the bombing on Farshoukh Street stands as a grim reminder of the extent of death and dislocation the Israeli invasion has wrought on the civilian population of this tormented nation of 3 million.

The magnitude of the crisis was driven home today when the Lebanese government made an urgent appeal to the United Nations for food rations and other relief supplies for 600,000 persons--one-fifth of the population--to carry them through the next six months.

Announcing the request, Samir Sambar, the chief U.N. spokesman here, predicted that "the dimensions of the human problem will overwhelm all others," including the political ones, as they become better known.

He said the main concern of relief agencies presently was logistics, how to get supplies here with Beirut's international airport still closed. Francesco Noseda, chief of the Geneva-based International Committee of the Red Cross, said his organization hoped to arrange for relief planes to land in Beirut Wednesday and for a boat full of food and other supplies to come into the port city of Sidon.

Now under Israeli control, Sidon is said to be the city where conditions are by far the worst.

As fragmentary reports begin to reach here from various corners of southern Lebanon, it is becoming increasingly clear that the Israeli invasion has caused wide human suffering among Lebanese and Palestinian civilians alike.

Fahti Arafat, the president of the Palestinian Red Crescent, or Red Cross, and brother of Palestine Liberation Organization leader Yasser Arafat, said in an interview today that he believed the death toll was even higher than official estimates, saying roughly 15,000 persons were killed and another 10,000 wounded.

While Noseda refused to criticize openly Israeli conduct during the war, he did say he believed there was "certainly a disproportion" between the heavy losses among civilians and those believed to have been inflicted on Lebanese and Palestinian combatants.

From all accounts, including those of Israeli officers and soldiers interviewed here during the past few days, the heavy Israeli sea, air and land bombardments of suspected Palestinian guerrilla positions, plus the generous use of high-powered weapons such as 2,000-pound bombs, cluster bombs and big rockets, have had a devastating impact on the civilian population.

Col. Amos Neeman, the military spokesman of the Israeli forces stationed outside the capital, confirmed in interviews with Western reporters yesterday that Palestinian targets had been softened up with artillery and air raids and blamed the heavy civilian casualties on the guerrilla practice of putting their positions inside towns, refugee camps and civilian homes. He did admit, however, that "some mistakes" had been made by the Israeli forces in their air, land and sea bombardments, presumably such as the bomb dropped on the Farshoukh Street building that killed 85 persons.

Dr. Abu Walid, chief surgeon of the Gaza Hospital in Beirut's Sabra Palestinian camp, said in an interview today that the rate of mortality among victims brought in for operations was very high. He said that during the l978 Israeli invasion of southern Lebanon it had been 15 to 20 percent but that this time it was between 30 and 50 percent.

He attributed the higher rate to the kind of the weapons being used by the Israelis.

Based on Red Cross, U.N., Palestinian and eyewitness accounts, this appeared to be the situation in various parts of the south:

Tyre. About 15,000 persons reportedly are suffering from the effects of the war there, 8,000, mostly Palestinians, living out in the open in need of "urgent relief."

Church and other relief officials last Friday provided food and milk to 350 Palestinians who fled from a nearby refugee camp and are now living in an orchard outside the town.

Sidon. About 300,000 residents of this port city, Lebanon's third largest, and its outlying surburbs are said to have fled to the nearby hills. Red Cross officials described the situation there today as "quite terrible" with the streets "full of bodies" and said there was an urgent need for food, shelter, water and medical supplies.

Jazzin. A city in south central Lebanon normally of 20,000, it is said to have become a major refugee center with 200,000 now camped in and around it. The road between Sidon and Jazzin is reportedly full of refugees as well.

Beirut. The city is overflowing with refugees living with relatives, in building lobbies, public schools and gardens and elsewhere out in the open. No estimates of the refugee population is available, partly because of much internal movement of Palestinians and Lebanese moving out of dangerous quarters to supposedly safer ones.

At some encampments, refugees had traveled all the way from Tyre in the far south sometimes by foot. Nefaila Fahrour, 38, and the 17 members of her extended family, including eight children, fled from Bass camp inside Tyre the first day of the Israeli invasion 10 days ago. Then they got a lift by car to Jazzin and from there walked three days to Beirut, a trip of 40 to 50 miles.

The family is now living in a public garden in central West Beirut under a tent attached to a tree.

Fahrour said she was forced to leave her children, 7 and 8 years old, behind in the rush to leave because they were out playing at a neighbor's home.

"We keep looking for a place to live, but it is good to stay here because we keep meeting neighbors and friends from Tyre," she said, hoping to hear of her children.