A Chinese company that assembles devices for Samsung Electronics Co. hired children at its production facilities and forced employees to work excessive hours, violating labor laws, China Labor Watch says in a new report.

Seven children younger than 16 were working in the factory of HEG Electronics (Huizhou) Co., a company assembling some Samsung products, according to the report issued Monday.

Child workers faced the “same harsh conditions” as adults and were paid only 70 percent of the wages of other workers, according to the New York-based group, which said it conducted investigations in June and July.

China Labor Watch previously published reports on explosions at factories and in 2010 accused Foxconn Technology Group, the assembler of Apple Inc. iPhones and iPads, of running a sweatshop in the country after a spate of suicides, a charge the Taiwanese company denied. The latest report said working conditions at HEG are “well below” those at Apple suppliers.

“The company has clearly violated Chinese labor laws,” China Labor Watch said about HEG Electronics. “A serious light needs to be shined on these issues.”

Four calls to two telephone numbers in Huizhou, southern China, listed on HEG’s website were unanswered, and an e-mail sent to the company’s designated address bounced back. HEG is a unit of Harbin Electronic Group Corp., according to its website.

Samsung Response

“Samsung Electronics has conducted two separate on-site inspections on HEG’s working conditions this year but found no irregularities on those occasions,” Nam Ki Yung, a spokesman for Samsung, said in an e-mailed statement. “Given the report, we will conduct another field survey at the earliest possible time to ensure our previous inspections have been based on full information and to take appropriate measures to correct any problems that may surface.”

Li Qiang, a director at China Labor Watch in New York, said one of his employees took a job at the factory to conduct the investigation and interviewed the seven children.

Overtime of between three to five hours a day in addition to the routine eight-hour work day is compulsory for HEG employees, China Labor Watch said in the report. Workers on HEG’s 11-hour night shift are given only a 40-minute break for meals, the labor rights group said.

“Child labor is a common practice in the factory,” the report said. Student workers amount to 80 percent of the factory workforce, it said.