The word is spreading fast among refugees in this enormous city of makeshift huts: within a few days a United Nations-sponsored camp will be ready to receive them.

For months Cambodians have been massing at 007, which sprawls across forestland that is apparently just on the Thai side of the ill-defined border with Cambodia. The camp is run by anti-Communist Khmer Serei (free Khmer) guerrillas who have emerged as a minor third force in the Cambodian conflict this year.

Conversations with Cambodian men and women today along the camp's dusty trails indicated news of the move has rekindled hopes for adequate food and medical care and a future with some security. Yet many expressed fear the Khmer Serei would try to hold them in the camp against their will.

If the civilians go, Khmer Serei officers appear to reason, foreign relief agencies will stop trucking in rice, there will be no young men to recruit and no black market to tax. The newly formed "liberation movement" would forfeit any political legitimacy it had acquired by governing large numbers of people.

"Everybody wants to go -- there's lots of medicine over there," said a male nurse working in a hospital tent almost totally devoid of medicine or equipment. "How many people will the Thais allow in?" another refugee asked.

Refugees seem most worried about security in their present camps. "It is comfortable enough here but we still hear the sound of gunfire," a peasant woman said sitting in her hut.

Military analysts expected Vietnamese troops backing the Heng Samrin government will soon begin a major sweep into the Khmer Serei zones. The Thai decision to move the civilians is apparently intended to deny the Vietnamese a target that might cause the war to spill into Thai territory.

Many refuugees gave embarrassed laughs when asked if they wanted to return to fight the Vietnamese. Questions they asked indicated most were more concerned with getting the better food a U.N. camp would have and gaining entry to third countries.

Refugees often cut short their conversations with reporters and shifted uneasily when armed Khmer Serei soldiers passed by. A Phnom Penh student claimed in a subdued voice that the troops had imprisoned people discussing "policy" with foreigners.

Seated at crude wooden tables in their command posts, Khmer Serei leaders at Camp 007 and 204 gave confused and contradictory explanations of how they would view people who opted out of the struggle.

"Suppose you were head of a liberation movement. Would you let people go?" asked Norodom Suriyavongn, a senior leader at 204. "A government has got to have citizens." Pressed on the question, he said he would not actually block departures but that able-bodied men should stay behind to fight the Vietnamese.

Camp 007's commandant, In Sakhon, a former officer in the American-supported Lon Nol army, first said only the sick and children would be allowed to go, then said "but everyone who wants to go is free to go."

In recent days representatives of the U.N. high commissioner for refugees have called on the Khmer Serei leaders to ask for their cooperation. Diplomatic sources said 204's officers refused outright.

The United Nations has no means to guarantee freedom of choice for people in the camps. The several thousand Khmer Serei troops believed to be in the area, many of them armed with AK47 automatic rifles, could physically bar people from leaving.

Serious trouble could arise if Thai troops attempted to enter and secure the camps. Two weeks ago, following an exchange of small arms fire with Khmer Serei troops, Thai mortars shelled another refugee camp, 511, killing scores of civilians. Tempers are still frayed and many of the soldiers who fled 511 have taken refuge in the other two camps.

Thailand has long tolerated the anticommunist Khmer presence on the border as a buffer against the Vietnamese army. But as the civilians' numbers have grown, and the Khmer Serei have put more men under arms and grown increasingly factionalized, relations with the Thais have broken down.

Indochina watchers contrasted the Thais' attempts to evacuate the Khmer Serei camps with the quick coopeeration the Khmer Rouge provided when their refugees were moved back last month to the camp at Sa Kaew. The highly disciplined Khmer Rouge cadres quickly obeyed Thai instructions to select people for relocation and over 30,000 people were moved almost without a hitch.

Despite the uncertainties, laborers and earth moving equipment hired by the U.N. continued to work feverishly today on the new camp below the mountain visible from 007. Relief agancies began raising hospital tents and setting up latrines. The camp, called Khao I Dang is being designed for 200,000 people.