Workers were found to be working as much as 100 hours of overtime a month. Photo/Associated Press.
Amazon has come under fire for dodgy employment practices that meant thousands of workers were hired and paid illegally.
A damning report by the New York-based China Labor Watch revealed the horrendous conditions dispatch workers were subject to while making Echo speakers and Kindle e-readers.
Dispatch workers, similar to contract workers in Australia, do not get sick pay or holiday pay and can be made redundant without wages during production slowdowns, according to The Guardian.
Contract manufacturer Foxconn says it is investigating the factory after the report was made public.
"We are carrying out a full investigation of the areas raised by that report, and if found to be true, immediate actions will be taken to bring the operations into compliance with our Code of Conduct," Foxconn Technology Group said in a statement.
The 94-page report followed a nine-month investigation of working conditions at a factory owned by Foxconn - the electronics manufacturing behemoth that produces parts for tech names including Apple, Microsoft and Intel.
Employees were subject to a gruelling 100 hours of monthly overtime, according to the report, which should have been no more than 36 hours under Chinese labour law.
It also found dispatch workers were employed at higher numbers than allowed.
Workers did not receive adequate safety training, according to the report, and staff dormitories were worryingly under-resourced and lacked fire extinguishers and escape routes.
The report noted staff were also subject to verbal abuse.
"All workers are subject to long hours and low wages," according to the report.
"As wages are low, workers must rely on overtime hours to earn enough to maintain a decent standard of living."
Amazon said it audited the factory in March and found overtime and use of dispatch workers were "issues of concern."
"We immediately requested a corrective action plan from Foxconn," Amazon said in a statement.
It said it is monitoring Foxconn's response and "compliance with our Supplier Code of Conduct. We are committed to ensuring that these issues are resolved."
It also found dispatch workers were employed at higher numbers than allowed.
Workers did not receive adequate safety training, according to the report, and staff dormitories were worryingly under-resourced and lacked fire extinguishers and escape routes.
The report noted staff were also subject to verbal abuse.
"All workers are subject to long hours and low wages," according to the report.
"As wages are low, workers must rely on overtime hours to earn enough to maintain a decent standard of living."
Amazon said it audited the factory in March and found overtime and use of dispatch workers were "issues of concern."
"We immediately requested a corrective action plan from Foxconn," Amazon said in a statement.
It said it is monitoring Foxconn's response and "compliance with our Supplier Code of Conduct. We are committed to ensuring that these issues are resolved."
Foxconn said in an emailed statement that it "works hard to comply with all relevant laws and regulations" where it operates and conducts regular audits.
"If infractions are identified, we work to immediately rectify them," it said.
In 2013, three Foxonn workers committed suicide at a Chinese factory. The company's "military management" was blamed for 17 worker suicides in 2010.
Working conditions at Amazon's US warehouses have also been criticised in recent times.
Bloomberg reported one lawsuit alleged the company got away with paying workers less by making them clock off before they faced security lines to leave the building.
And in the UK, Amazon workers were found to use bottles in lieu of the bathroom to avoid taking too long away from the job.
Taiwan-based Foxconn is the world's largest contract electronics manufacturer and employs more than a million people.