A factory district just outside Shenzhen, Fuqiao Industrial Park, is a snapshot of the economic troubles rippling through the region. Several small factories in the park have closed in recent months. At Wang Jinda Industries, the lettering had been scraped off the entrance after the owner closed last week. Two customers had arrived for a shipment of goods only to find an empty factory.

Meanwhile, some factories that remained open were struggling. Workers at a large printing factory said the owners had stopped recruiting new workers in September while many others had quit. Several workers said wages had dropped significantly as the owners were reducing the length of shifts. A few workers accused owners of deliberately trying to drive down wages to force workers to quit. “Everybody is worried,” said Lin Baozeng, 26, a cashier at a canteen inside the industrial park. Her daily lunch crowd has dwindled to about 100 migrant workers from 500.

“If the economy is bad,” Ms. Lin added as her 3-year-old daughter played nearby, “how can I afford to raise my child?”

As yet, gauging the scale of factory closings remains difficult in Shenzhen and surrounding Guangdong Province, the country’s main export engine. Guangdong was already making a concerted effort to move up the manufacturing value chain at a time when rising labor costs and greater government regulations were making some smaller, cheaper exporters unprofitable. But the recent export slowdown is having an unanticipated impact. More than 7,000 small- and medium-sized factories have closed in recent months. Shenzhen’s mayor said 50,000 people in the city alone had lost their jobs in the last few months.

Image In Shenzhen on Thursday, a portrait of Deng Xiaoping was a backdrop for passers-by. Credit... Ym Yik/European Pressphoto Agency

And there are mounting signs that the problems could be far broader. Over all, China’s economy will continue to expand next year, but some economists say the rate of growth could fall as low as 5 or 6 percent, far slower than the double-digit pace of the preceding several years.

State media have reported that 4.85 million migrant workers have returned to the countryside early before next month’s annual Lunar New Year holiday. Some inland provinces have already announced subsidies for unemployed returnees. On Thursday, the country’s official news agency, Xinhua, reported that 6.5 million migrant workers may be jobless next year.