Prince Norodom Sihanouk, the ruler of Cambodia from 1941 to 1970, is urging the United States and other governments to call an international conference on Cambodia. "Otherwise" he says, the "entire Cambodian people may disappear."

In an interview in his suite at the Hotel Geore V in Paris this month, Sihanouk said he is now persuaded that the Vietnamese will never surrender Cambodia unless it is clearly too costly to them and their Soviet patrons. But Sihanouk acknowledges the dilemna that continued resistance will mean even more Cambodians dying.

"In a conference the key countries are China, the U.S.S.R., and Vietnam," he said. "But at the moment China wants Cambodians to continue the war against the U.S.S.R. and vice versa. I think the U.S.S.R. has more reason to refuse to come to a conference; they feel they have the country in their hands. But it is foolish of China to think it could get back Cambodia with Pol Pot and the Khmer Rouge. It would be more intelligent of China to cooperate with the Western powers to end the violence by supporting Sihanouk."

Sihanouk already has some support from the French government and has formally asked the British government to call for reconvening the 1954 Geneva conference, which guaranteed Cambodia's neutrality.

In London, Foreign Office officials are known to be studying his requests.

But British officials feel that so much has changed since 1954 that Britain and the Soviet Union are not necessarily the best chairmen for a new conference.

In Washington, State Department officials agree that a political compromise to ensure the neutrality of Cambodia is essential for the stability of the area and particularly for Thailand.

In the last 10 years the Cambodian population is thought to have been reduced from around 7 million to around 4 million people. The survivors are now threatened by famine and war.

The Vietnamese now have an army of 200,000 men in Cambodia, fighting the remnants of the Khmer Rouge government and other resistance groups. There is a serious risk of the war spilling into Thailand and of China attacking Vietnam a second time to "punish" it for its attempt to domimate Cambodia.

In search of a compromise, Prince Sihanouk is now in Paris as the guest of the French government. Earlier this year France had refused to allow him to come unless he promised to refrain from political activities. From Peking, Sihanouk protested that if Iran's Ayatollah Ruhollah Khomeini had been allowed to make his case from Paris, Sihanouk should be given the same facilities. The French government has now apparently stopped trying to work out a settlement of the Cambodian crisis directly with Vietnam. Instead, France's permission for Sihanouk to go to Paris indicates that France is now supporting him.

Sihanouk did not rule out the United Nations providing the machinery for a new conference. On Nov. 13 the General Assembly passed a resolution proposed by five Southeast Asian nations calling on the secretary general to explore the possibility of holding an "international conference of Kampuchea" and to report to the assembly on the situation "at the earliest possible opportunity."

The 1954 Geneva conference was adjourned and so could in theory be recalled. "Why create a new organization?" he asks. "A basis and machinery already exist. The 1954 conference was not perfect, but it was something good." He proposes that the 1954 conference should be enlarged to include all the countries of the region including Australia and Japan. He would also like Yugoslavia, as representative of the nonaligned, to play an important part.