Foxconn Technology Group workers returned to the assembly line in Zhengzhou, China, that makes the Apple iPhone 5 after walking off their jobs Saturday, advocacy group China Labour Watch said.
A dispute occurred between the production and quality teams at the factory, but it was resolved by Saturday afternoon, Simon Hsing, a spokesman for Hon Hai Precision Industry Co., Foxconn's flagship unit, said in a phone interview.
"Three to four thousand" production employees walked off the job at the plant Saturday. They returned to work Sunday after management said they would be fired if they failed to turn up, executive director Li Qiang said.
The workers' action occurred after they were being made to work through the Chinese holiday week, and being made subject to what they called "overly strict" product-quality demands without adequate training, the group said in a press release dated Oct. 5.
The walkout was the result of demands placed by Apple on its manufacturer to improve the quality of the iPhone 5 after customers complained that the company's latest handset had scratches, China Labour Watch said.
The Taiwan-based company acknowledged in a statement that two isolated labour disputes erupted at its plant in Zhengzhou on October 1 and 2, but said they were immediately addressed and that production of the iconic phones continued.
The disputes marked the latest unrest to hit Foxconn, whose factories in China have been beset by a string of worker suicides in recent years, and follows a massive brawl at one facility last month.
"Any reports that there has been an employee strike are inaccurate, there has been no workplace stoppage in that facility or any other Foxconn facility and production has continued on schedule," the Foxconn statement said.
"Employees who have worked during the China national holidays at all our operations in China have done so voluntarily and this is supported by written documentation and any reports to the contrary are inaccurate."
The China Labour Watch, citing workers at the plant, said the work stoppage resulted in "a state of paralysis" to multiple iPhone 5 production lines.
Foxconn is the world's largest maker of computer components and assembles products for Apple, Sony, Intel and Nokia, among others.
Its vast plants in China employ up to 1.2 million workers, with nearly half of them at a sprawling complex in Shenzhen, in the south of the country.