Most of the 42,000 Cambodians forcibly repatriated by Thailand in mid-June have been marched deep into the country-side by troops of the pro-Vietnamese government headed by Heng Samrin, according to refugees who escaped back into Thailand.

A 35-year-old Khmer woman, interviewed by refugee officials in Thailand, said that she and thousands of other people walked south to the town of Kompong Thom after being forced back into Cambodia. Vietnamese soldiers provided food for three days at a time, she said.

After reaching the town, about 120 miles ffrom her point of entry in Preah Vinear Province, the woman split from the main body of people and bribed her way onto vehicles headed north past the town of Siem Reap to the Thai border and crossed over.

Officials of the Heng Samrin government have told the Swedish Red Cross that about 6,000 people are still camped out in the desolate, mine-strewn valley into which the group of 42,000 was pushed by armed Thai troops.

Justifying the situation, Thai officials said their government could not play host indefinitely to tens of thousands of Cambodians who had streamed in since the Vietnamese invaded Cambodia in December.

The expulsion of Cambodians from Thailand prompted a barrage of protest from political figures around the world. As a result, the Thai government postponed plans to send back another 40,000 Khmers now in camps in southeastern Thailand.

It also granted permission to stay to about a thousand repatriated refugees who somehow had managed to cross back into Thailand. Foreign resettlement agencies are working quietly to move these people to third countries as quickly as possible, in case the Thai government should change its mind.

Indochina analysts here are working with scant information on the fate of those who followed the Vietnamese troops south into the Cambodian heartland. Speculation is rife on whether they are being fed, put to work, drafted to fight the remnants of Pol Pot's Kmer Rouge Army, or left to fend for themselves.

The Cambodian government has said that most have returned to their home villages. Analysts here point out, however, that the refugees were predominantly ethnic Chinese, a group that the Phnom Phen government apparently believes does not fit into the new society.

The woman refugee claimed that the ethnic Chinese -- were the target of discrimination by the Vietnamese. On reaching Kompong Thom, people were told that Khmers could go and settle anywhere, but the ethnic Chinese could not settle in any town or city.

Indochina watchers here noted that in past months ethnic Chinese refugees arriving in Thailand have told similar stories of being denied access to towns, an apparent attempt to block the reestablishment of an urban mercantile class.

Attempts by the Swedish Red Cross to send food directly to the repatriated people -- an idea supported by Thailand -- appear to have reached a stalemate.

Officials of the Cambodian government insist that any aid must pass through the central government. The Swedes, apparently fearing that food sent on those terms would be diverted to Vietnam or the Army, have sent their chief negotiator home.

Men and women among the 1,000 wo made it back to the Thai side have told grim tales of Thai soldiers forcing people down the slope of a 1,500-foot ridge that divides the two countries.

The Thai government, for its part, maintains that repartriation was not forcible. A Foreign Ministry spokesman said that the head of each family crossing back gave consent in advance with no coercion.

Most analysts here, however, dismiss this verion of events and say repriation was a calculated measure meant to demonstrate to the Western world the weight of Thailand's refugee burden. CAPTION: Map, no caption, Dave Cook -- The Washington Post