Officials of the Vietnamese-installed, Soviet-backed government here show signs of serious concern that the U.N. conference on Cambodia, currently in session in new york, could set back its efforts to gain legitimacy in the eyes of the Cambodian people.

The government-controlled news media have been at pains for the last several days to report international opinion against the conference, trumpeting protests by such countries as Mongolia in addition to Hanoi and Moscow.

Phnom Penh officials reject the aims of the conference -- withdrawal of 200,000 Vietnamese troops from the country, introduction of a U.N. peacekeeping force and free election of an independent government -- out of hand, and scoff in particular at the notion of U.N. troops ensuring security in Cambodia after a Vietnamese withdrawal.

"You see how U.N. troops ensure peace in Lebanon and how effective they are there,'' said Chum Bun Rong, director of the Foreign Ministry's press department in the People's Republic of Kampuchea, as the Phnon Penh government is called.

Officials say the governmment, reinforcing its refusal to compromise, is prepared to weather possibly severe economic difficulties next year stemming from a sharp reduction in foreign aid when U.N. relief agencies terminate their masive emergency program as scheduled at the end of the year.

"Why didn't the U.N. hold a conference on Kampuchea when Pol Pot was massacring the people?" another Foreign Ministry official asked. "If not for the Vietnamese, Pol Pot would come back and commit more massacres."

He and other government spokesmen argue that a Vietnamese pullout would lead to the return of the communist Khmer Rouge forces under Pol Pot, who was driven from power in january 1979 after four years of brutal rule when Vietnamese troops invaded Cambodia and installed another communist government headed by a protege, Heng Samrin.

A representative of the Khmer Rouge, Ieng Sary, is at the U.N. conference, which is being attended by 83 nations including Western countries and Vietnam's noncommunist Southeast Asian neighbors. Vietnam, the Soviet Union and their allies are boycotting the meetings.

Western relief officials based here lament that no group on either side of the dispute genuinely represents the Cambodian people, whose interests they feel have been sublimated by international political rivalries.

From their observations, ordinary Cambodians tend to wish the Vietnamese troops would go home, but fear the return of Khmer Rouge far more than they dislike the Vietnamese presence. If they were free to choose, the officials say, the Cambodians they know would rather have no noncommunist than a communist government.

Even government officials acknowledge that Cambodians remain fearful of communism after the ravages of the Khmer Rouge.

"The term Communist raises fear among the people, and this is why the aftermath of the Pol Pot regime left the new regime the great task of showing the people the real socialism," said Chum Bun Rong. Although he denied being a Communist Party member himself, he added, ""We cannot apply anything but socialism in Kampuchea."

According to aid officials, Cambodians in areas under the government's control generally see resigned to having no choice in determining their affairs for the foreseeable future.

However, the officials detect a certain acceptance by Cambodians of the Henge Sarin government, which so far has shown itself to be much less severe and doctrinaire than Hanoi's administration in Vietnam. The government's strongman, Council of Ministers President Pen Sovan, has encouraged the establishment of a free market in Phnom Penh, where commerce was destroyed when the Khmer Rouge drove out the city's inhabitants in 1975.

Although there are indications that the free market may be only a temporary measure until the government can restablish state-run enterprises, the shops and stalls currently appear to be thriving. A food market is well supplied with various goods including vegetables, meat, rice and even cookies, and hundreds of other stalls sell products ranging from nuts and bolts to cosmetics. Most of the merchandise is smuggled from Thailand.

However, prices are high compared to the average salary of 100 riels ($25) a month. For example, beef is 20 riels ($5) a kilo (2.2 pounds) and pork costs 25 riels ($6.25) a kilo. Rice is relatively inexpensive at 2 riels (50 cents) a kilo. The new currency introduced by the government -- Pol Pot had abolished the entire monetary and banking system -- is widely used here.

Other points in the government's favor have been in efforts to restore health care and Cambodian culture. Hundreds of Cambodians flock to a newly opened theater every evening to see a 14th century play featuring traditional music and dancing.

According to aid officials, Cambodians appear less enthusiastic about lengthy "political education" sessions that the government requires them to attend, often at the expense of time at key jobs such as hospital work. Cambodians at one hospital here reportedly spend an average of 10 days a month in the courses, and some employees are obliged to attend for three months at a stretch.

Last year there were reports of disappearances of some Cambodians who never returned from polticial education courses, but these reports are much less frequent now, and Cambodians here generally are less frightened of the government than they were 10 months ago, one Western official said.

Any Western residents here have done much soul-searching about the international opposition to the Phnom Penh government and the Vietnamese occupation. Most seem to have come to the conclusion that, as one American put it, Hanoi's presence here "is a marriage between Vietnam's vested interests and Kampuchean interests." He said that on his return to the United States, he would tell his friends, "We ought to leave these people alone."