In addition to saving on costs, automation is also crucial to boosting accuracy and quality, Chen said. The "new hands" have brought down the proportion of substandard products to 5 percent from 25 percent and more than doubled productivity, he said.

As of January, 1,032 Dongguan companies applied for government subsidies for industrial automation, while shouldering more than 10 billion yuan ($1.53 billion) for their automation programs, according to the city's economic and information technology bureau.

The manufacturers saw productivity up by 65 percent and costs down by about 10 percent on average, and their work force is expected to be trimmed by more than 71,000, said Liu Yuqing, the bureau's chief economist.

Increased automation helps relieve workers of repetitive, dangerous and onerous tasks, said the city's Party chief, Xu Jianhua.

The drive has buoyed the robotics industry in Dongguan. Last year, about 400 companies producing robots, with more than 55,000 employees, achieved output of 26 billion yuan. The number is expected to quadruple by 2020, a goal set in a directive issued by the local government to bolster the industry in January.

The document also announced measures to fund automation of cost-sensitive small and medium-sized manufacturers. The city wants 80 percent of its manufacturers to automate factory work by the end of 2018.

Job killers?

As workshops fill with robots, concerns have mounted about a shortage or jobs for humans. But in Dongguan, workers are safe for now.

A survey of manufacturers that have switched to automation showed that only about 20 percent of them resorted to layoffs, while some of the remaining have even hired more workers, said vice mayor He Yu.

Laid-off workers can easily find new jobs in other factories or the service sector, as job seekers in Dongguan get 1.2 offers on average, He said.

However, a sense of insecurity has grown among workers. In the past, many were spoiled by increasingly generous pay due to the labor shortage, and workers neglected to update their skills.

Chen Haibo, 28, is grateful that he secured a spot at an automation training program in early 2014. "I had three rounds of interviews. If I had not made it, I'm afraid I would be transporting bricks at a construction site right now," said the automation specialist at a Taiwan-invested plant.

The robot rivals have brought other changes to Dongguan's work force. Statistics from the city's employment authorities showed that the number of young and middle-aged workers last year saw an increase of 2.3 percent from 2014.