The Israeli Army is allowing the Red Cross to resume food convoys into besieged West Beirut but is maintaining a total blockade of fuel shipments, Lebanese and international aid officials said today. They warned of a dangerous breakdown in hospital and sanitary services if the cutoff of gasoline continues.

Dr. Abdel Rahman Labban, Lebanese minister of labor and social affairs, and Jean Jacques Kurz, Red Cross spokesman, said that the flour and rice shipments the Israelis began to allow through the blockade again on Saturday--after a day's cutoff--may, ironically, go uncooked eventually if fuel supplies do not come into the area soon.

"They're letting us take in 185 tons of flour and rice a day," enough to feed about 100,000 people, Kurz said. "There could be a problem if the shortage of fuel worsens and the bakeries cannot cook bread," he added. "We are still not allowed to bring in fuel oil."

Kurz added that the shortage of all types of fuel in West Beirut is reflected in taxi fares of $30 for a one-mile trip. "That is four or five times the average price," he said.

If the Israelis continue to keep fuel shipments out of West Beirut much longer, "kerosene will become as important as blood" to the section's hospitals, which rely on it to run emergency power generators for operations and to run X-ray equipment, said one official of a humanitarian organization. Another emergency aid official said the system of water distribution to neighborhood tanks set up two weeks ago by UNICEF in West Beirut could "soon begin to break down" as water tank trucks run out of gasoline.

A tour of West Beirut on Sunday showed mounting piles of partially burned, foul-smelling garbage, uncollected because refuse trucks lack gasoline, Lebanese officials said. In a number of places, children played and adults washed under the hot dry-season sun in water-filled bomb craters and where broken mains gushed clear water. Numerous sections of West Beirut lack water.

The Israelis began the blockade on July 3 to put pressure on the estimated 6,000 Palestine Liberation Organization guerrillas holed up in West Beirut. The Israelis have vowed not to leave Lebanon until the PLO has withdrawn to another country or is destroyed as a military threat to Israel.

Israeli Army spokesman Col. Paul Kedar said this morning that the Red Cross shipments had been stopped on Friday because the Israeli Army had agreed last week to allow only four Red Cross food convoys to cross into West Beirut. Medical supplies can still cross at any time, Kedar added.

"It is not a routine thing for Red Cross food convoys to cross into West Beirut," Kedar said. "The Red Cross will have to reapply" after each authorization has expired, Kedar added.

[In Jerusalem, Sen. Alphonse D'Amato (R-N.Y.) said that Prime Minister Menachem Begin had assured him that "there would be no interruption of food supplies, of water and of electricity" to West Beirut so as to minimize the effect of the Israeli siege on the civilian population, Washington Post correspondent David B. Ottaway reported.]

[In Washington, Israeli Economics Minister Yaacov Meridor told a news conference, "The Israeli Army is under strict orders not to prevent supplies of food, water and electricity from entering Beirut." Meridor said "there is no limitation" on truck convoys carrying supplies into the city.]