The bedraggled refugees have been fleeing here for years, turning this rugged frontier outpost into a halfway house for Vietnam's castoffs.
But the great exodus of ethnic Chinese from Vietnam that transformed south China is finally coming to a close.
Ningming and other refugee centers along the Sino-Vietnamese border once bulged with thousands of daily arrivals, Vietnamese of Chinese descent who had been driven out of their adopted land as relations between Hanoi and Peking worsened in 1978.
Tiny southern towns suddenly were forced to feed and house whole communities of strangers who spoke different languages and practiced different customs.
The migration began to slacken after 1980 but showed no signs of ending until this year when fewer than 150 ethnic Chinese crossed the border in the first three months, according to U.N. refugee officials.
Ningming, the center that once processed as many as 400 refugees monthly for assignment to state farms, has only received six newcomers so far this year.
"We're winding down our operations," said a U.N. official who works with the refugees. "There isn't much left to do."
The newest arrivals are believed to be the last remnants of northern Vietnam's once-thriving Chinese community that had lived peacefully for generations until the months leading up to the Sino-Vietnamese border clash of February 1979.
Unlike the earlier refugees who had been stripped of their belongings and forcefully evicted as pro-Peking spies, the latest batch had to bribe their way out of Vietnam.
Most are seeking passage to a third country in North America or Europe, refusing to work on the string of state farms that China set up to house the 272,000 ethnic Chinese who have fled Vietnam since 1978.
Instead, the newcomers become semipermanent residents of the jerry-built reception centers like Ningming's, waiting to hear from foreign consulates in Peking or Canton.
"If I don't get to the United States, I shall be very sad and fall ill," said Tran Ly Sang, 29, who arrived here in April after an arduous journey with hopes of eventually reuniting with relatives in Atlanta.
Although Peking has been patient in resettling the refugees, the costs have been burdensome. At least $600 million is said to have been spent to house, feed and clothe them.
Roughly half of the new immigrants reportedly are self-sufficient now, earning incomes at state farms in four southern provinces where their sugar, fruit and tea crops strengthen local economies.
At Qu Yang state farm outside Ningming, 650 refugees turned barren wilderness into a profitable pineapple and citrus fruit grove, earning themselves good incomes by Chinese standards.
With their profits, they have built new barracks-style housing and opened a primary school and nursery.
"The work is very hard and it's hot here," said a middle-aged woman from Haiphong. "But nobody bothers you, and we have enough to eat."
Still, the thought of escaping Vietnam for the austerity of a Chinese state farm has little appeal to many refugees who risked their lives and paid bribes of up to $2,000 to cross the border.
Chen Yongsan, 26, has been at Ningming for 2 1/2 years waiting for permission from U.S. immigration officials to join his family in California.
Chen's parents paid the equivalent of $4,500 to bribe the family's way onto boats leaving Vietnam in 1979, but the young man's vessel was intercepted by Vietnamese authorities and he was banished to a "new economic zone."
"We had nothing there," he said of the zone. "We lived in a tiny house with seven or eight people to a room. All we ate was corn. Life was very bitter."
He escaped in 1980, paid a Vietnamese official to "guide" him to China and checked into Ningming in November of that year.
Now, he whiles away his days in his small, bare room in the refugee camp, subsisting on the 30 cents worth of food provided by the government each day and dreaming of the good life in the United States.
The chances of finding a third country sanctuary is said to be slim because of tightening immigration restrictions in the West. Fewer than 1,000 ethnic Chinese have managed to resettle abroad after coming to China.
Neverthless, Chinese officials say their doors will remain open.
"Our job is not done until the last refugee leaves," said Ningming's director, Ziang Guangming.