When Foxconn made headlines in 2010 following a spate of worker suicides at a Shenzhen factory that makes iPhones, it was probably the first time many people in the West had heard of the manufacturing contractor giant.

In the years after, rights groups and workers said conditions at the plant had improved. But a new report from a watchdog is now drawing attention to another Foxconn facility -- one located in a city far less well-known than Shenzhen.

A production line at the Foxconn complex in Shenzhen in 2010 (Picture: AP Photo)

China Labor Watch says their months-long investigation reveals harsh working conditions in a factory in the southern city of Hengyang in Hunan province. It mostly makes Amazon products, including Echo Dot and Kindle.

The factory is accused of relying heavily on so-called dispatch workers -- those who are employed through agencies rather than by Foxconn itself. While factories are required by Chinese laws to limit dispatch workers to 10% of the staff, the Foxconn plant had 40%.

Dispatch workers, who are paid 14.5 yuan (US$2.26) an hour, don’t get paid extra for overtime and aren’t entitled to paid sick leave. They also go through the same long hours as regular employees.

An undercover investigator sent by China Labor Watch said she was expected to clean 1,400 Echo Dot speakers during an 11-hour overnight shift, using a toothbrush dipped in rubbing alcohol to wipe off dust.

Another day, she spoke with a 45-year-old woman who complained that her hand was growing numb because of the repeated brushing. She said her body was so sore, her “back and arms could barely take it anymore”.

Foxconn’s Hengyang plant primarily manufactures Amazon products, including its Alexa-enabled speaker Echo Dot. (Picture: AP Photo)

This comes as Amazon faces criticism over allegedly abusive conditions at its warehouses in the UK. A survey by worker rights platform Organise found that three in four workers skipped bathroom breaks for fear of missing their target and being disciplined as a result. Amazon told The Verge, “we don’t recognize these allegations as an accurate portrayal of activities in our buildings.”

As for the allegations in China, Amazon said it had found “issues of concern” in the Hengyang factory during an audit in March, and "immediately requested a corrective action plan”. Foxconn told Reuters it is carrying out its own investigation and will rectify any misconduct it finds.