Cambodia faces a grave danger of famine, which could create new tides of fleeing refugees, Secretary of State Cyrus R. Vance and other State Department officials told a Senate hearing yesterday.

The United States has been frustrated in its efforts to work through international organizations and other governments to head off starvation, according to the State Department witnesses. The United States is prohibited by law from aiding Cambodia directly.

Sen. Edward M. Kennedy (D-Mass.), who raised the issue in a hearing on Indochina refugees said the United States should "redouble our efforts" to break through procedural and political log jams that are holding up food assistance. Part of the trouble, Kennedy said, is a credentials fight at the United Nations over rival Cambodia regimes "when we are about to see hundreds of thousands of people starve."

Cambodia is the front line in a war involving combat elements and proxy forces of Soviet-backed Vietnam and its communist foe, the People's Republic of China.

The international political maneuvering centering on hapless and battered Cambodia has become intense, complicating the policies of the United Nations and others looking on.

"Without a political solution the bloodshed will continue," said Vacne, who called for a political conference in search of a settlement. He said the United States has been in diplomatic discussions with Vietnam, the Soviet Union, China and Southeast Asian states about political solutions and will continue its discussions with all those nations.

State Department officials said they do not know on the basis of very sketchy reports how serious the Cambodian food situation will become. They said that at a minimum there will be severe localized shortages, and that extensive famine is considered a real possibility.

The Vietnamese invasion and occupation of the past seven months, along with continued insurgency of Chinese-backed Pol Pot forces, has disrupted the planting of rice, the food staple of Cambodia. The coming harvest may be also in danger.

Cambodia is believed to have a population of about 5 million after severe bloodletting from bombing, ground fighting, massacres and disease. The majority of the people are under control of a Vietnam-sponsored Heng Samrin regime centered in Phnom Penh, and a minority under the control of the Chinese-backed Pol Pot rebels, according to U.S. officials. A substantical number of people are living in a no man's land outside of effective control of either side.

The Hanoi-backed regime recently turned down an offer by the Swedish Red Cross to set up a food relief program for starving civilians in a north-western Cambodia province, reportedly for fear that the food would fall into the hands of the rebels.

Earlier, the International Committee of the Red Cross reportedly was told by the Phnom Penh authorities that no food is needed, but Red Cross officials are in the Cambodian capital now for further discussions.

Ambassador Dick Clark, the State Department's refugee coordinator, told Kenneday the United States is prepared to work with "any qualified international group" to head off famine in Cambodia. So far the United States has provided a small amount of aid to Thailand for feeding Cambodian refugees fleeing to that country.

In view of the centuries-old conflict between Vietnam and Cambodia, American officials are not surprised at reports that the Vietnamese occupation is in trouble despite the presence of about 200,000 of Hanoihs troops.

Prince Norodom Sihanouk, the former Cambodian chief of state, has called for an international conference and has begun maneuvering to return to power as leader of a neutralist regime.

Sihanouk, who has close ties with China and with many non-aligned nations, may put on an international political campaign against the Vietnamese in coming months, while China steps up its backing for the military insurgency. CAPTION: Picture, Secretary Vance, Sen. Kennedy confer before hearing on Indochinese refugees. By James K.W. Atherton - The Washington Post