U.S.-based China Labor Watch (CLW) has upgraded this week its scathing review on Samsung's labour practices, highlighting what the activist group called as "illegal and inhumane treatment," of young Chinese workers tasked to assemble a host of Samsung products.

The new CLW report faulted Samsung contractors for "severe labour abuses," in eight Chinese facilities that were designed to "manufacture cell phones, DVD players, mobile displays, air conditioners and other electronics and related parts for Samsung."

More than 20,000 workers were subject to what appeared as routine infractions of workers' rights that even by Chinese labour standard would be deemed abhorrent and illegal, CLW said on its report.

These Samsung employees were deployed in factory compounds located in Tianjin, Weihai, Huizhou, Suzhou and Shenzhen, based on its investigation that the New York-based CLW said was conducted from May to August 2012.

It served as a follow through on CLW's August press briefing that revealed the presence of child labour and other work environment violations at HEG Electronics, which Samsung has confirmed was one of its key Chinese contractors.

The first report prompted Samsung to order an audit that led to its admission that HEG indeed has been exposing its workers to unsafe labour conditions, with the attendant assessment that the Samsung manufacturer "has inadequate management practices."

The South Korean tech giant strongly urged HEG officials to immediately roll out improvements lest Samsung will look elsewhere for other suppliers.

Yet according to CLW, Samsung may not be probing too extensively as its new report pointed to "a long list of severe labour abuses."

The tech giant's Chinese contractors have been subjecting their hapless workers to "forced overtime work per month, unpaid work, standing for 11 to 12 hours while working, underage workers, severe age and gender discrimination, abuse of student and labour dispatch workers, a lack of worker safety, and verbal and physical abuse," the CLW report said.

And what really caught the attention of CLW probers was the plight of the exclusively female factory workers of Tianjin Intops Corporation, which the report said were made to bear cruel working conditions.

The 1200-strong Tianjin workforce "must work standing for 11 hours per day," while under the constant watch of verbally abusive supervisors and guards, the report said.

Apart from enduring physical and emotional stress, these workers were being pushed to the limit of legal working hours and were grossly underpaid, the American labour group said.

For a global firm that rakes in billions of dollars in annual revenues, Samsung should act solidly and immediately to erase "this sort of illegal and inhumane treatment (that) is rampant among Samsung's factories and supply chain," CLW said on its report.

Samsung said that a review process on all its Chinese contractors were now underway, which covers about 250 manufacturing partners of the tech firm in mainland China and with results to be issued between September and December this year.

These moves, the company told BGR News in an earlier statement, were in line with its strict adherence to "the highest standards of working conditions."

"We try to maintain that at our facilities and the facilities of partner companies around the world," the Samsung statement added.