PRAGUE — For Trieu Dinh Van, 25, the long journey two years ago from the rice paddies of northern Vietnam to a truck-welding factory in eastern Bohemia was supposed to provide an economic lifeline. Instead Mr. Van, the son of poor, peasant farmers, is jobless, homeless and heavily indebted in a faraway land.

Mr. Van said his elderly parents put up the family farm as collateral for a loan of €10,000, or about $14,000, to pay an agent for his plane ticket and a working visa. But less than a year after he arrived in the Czech Republic, the global financial crisis claimed his €8-an-hour job at Kogel, a German truck manufacturer, and he can no longer send money home. Now he fears he will have to ask his family for a handout to survive.

“It would not be good for me to go back to Vietnam,” he said on a recent day, wondering where he would spend the night. “I would return home with empty hands and couldn’t marry or build a house. That would be a great shame for me.”

Mr. Van is one of 20,000 Vietnamese workers who arrived here in 2007, part of an influx of poor from Vietnam, China, Mongolia and elsewhere who were recruited in Eastern Europe to become low-skilled foot-soldiers for then-booming economies. But when economies across the region began to contract earlier this year, thousands became jobless and dispossessed.

In Romania, hundreds of Chinese migrants camped out in freezing temperatures in Bucharest for several weeks to protest against contractors who had stopped paying them.

Czech officials say they fear social unrest as exports plummet and unemployment, which economists say could hit 8 percent by the end of the year, pushes ever more Czechs to seek the low-wage work they once left to foreign laborers.

Although several thousand Vietnamese who came to Communist Czechoslovakia under fraternal work programs in the 1970s have successfully carved out a niche here, friction remains. The Czech government hopes that jobless migrants will go home because it fears that unemployed migrants could aggravate an already simmering backlash against minorities.

Last month, a Roma child and her parents were severely burned after suspected rightist radicals firebombed their home in the northeast town of Vitkov. Some in the Vietnamese community fear they, too, may be targeted.

“The Czechs don’t like us, because we look different,” said Mr. Van, who added that he had already been accosted in Chocen, the small town in eastern Bohemia where he worked, by local residents shouting, “Vietnamese, go home!” Vietnamese laborers, he said, were also denied access to discos and restaurants.

Under a policy begun in February, any unemployed foreign worker who wants to go home is eligible for a free one-way air or rail fare and €500 in cash. In the first two months, about 2,000 Mongolians, Ukrainians and Kazakhstanis took up the offer. But many Vietnamese like Mr. Van, who are saddled with debts, prefer to stay and wait for better times.

Ivan Langer, who as interior minister devised the return policy, said he worried that an estimated 12,000 jobless foreign workers were vulnerable to being drawn into organized crime, or being exploited as slave labor.

According to the National Anti-Drug Center, the police last year uncovered 79 large-scale marijuana grow-shops, 70 of which were run by Vietnamese. A Vietnamese man from the southeast city of Brno, suspected of heroin dealing, was beaten to death by the police in January.

Julie Lien Vrbkova, a Vietnamese expert who has worked as a translator at several automobile factories employing Vietnamese workers, said she had been shocked by “slave-like” working conditions, including 12-hour days during which workers were beaten if they stopped working.

Despite recent tensions, the Vietnamese community in the Czech Republic is one of Central Europe’s most abiding minority success stories. Many own thriving corner shops, speak Czech and send their children to Czech schools, where they are routinely at the top of their classes.