Hong Kong (CNN) -- The biggest manufacturer of iconic Apple products including the iPhone and the iPad has again come under fire for the alleged treatment of its workers -- this time by a Hong Kong-based rights group.
Workers at Foxconn's giant plants in the Chinese cities of Shenzhen and Zhengzhou are subjected to long, punishing shifts for low pay, regular humiliation and harassment by management, and harsh living conditions in cramped factory dormitories, according to a report released Thursday by Students and Scholars Against Corporate Misbehavior (SACOM).
But questions about working conditions at Foxconn's Chinese plants are nothing new.
The Taiwan-based electronics supplier -- which also makes electronic goods for Sony, Microsoft, Nokia and other household brands -- came under intense scrutiny by CNN and other media outlets in 2010 after a series of suicides by workers at its Chinese plants raised questions about living and working conditions.
Though Foxconn maintains its workers are treated well, Chairman Terry Gou made an unprecedented public apology in the wake of the suicides.
Foxconn then released a statement saying it had introduced counselors, started a 24-hour phone counseling service and opened a stress room where workers can take out their frustration on mannequins with bats.
The statement concluded by saying Foxconn was "not perfect" but had made "tremendous progress" with the positive impact its programs were having on employees.
Thursday's report was based on interviews conducted with more than 170 workers -- mostly from production lines -- between March and May of this year. Most of the interviews took place away from Foxconn production plants, though some workers ultimately refused to speak, explaining they had been warned in their orientation not to talk to journalists, SACOM said.
"Some workers felt the most pressing issue is their treatment by management, while others felt pay was the main issue. But most agreed they had witnessed no significant improvements," SACOM's Debby Chan Sze Wan told CNN, referring to pledges Foxconn has made since 2010.
Despite overall increases to basic salaries introduced by Foxconn, the report said many workers claimed they were ultimately worse off as paid overtime hours were reduced. But they were frequently set tougher production targets and even required to work unpaid overtime.
Others complained of humiliating disciplinary measures including forcing workers to write confession letters about mistakes made and to clean toilets. One woman, indentified as Chen, who joined Foxconn in November 2011, told her interviewer she was punished for declining overtime work on a Saturday. Her supervisor did not approve it, but she did not go to work on that day. As a punishment she was asked to move 3,000 boxes a day during the work shift, she said. This lasted for 10 days and resulted in her suffering from back pain.
The report also questioned safety standards at the Foxconn plants. There appeared to be no adequate training on work and safety, with workers often unaware of the kinds of chemicals they were using in the production process, the report said. It said at least 728 cases of industrial injuries at Foxconn's production facilities in Shenzhen had been recorded.
Living conditions in the dormitory blocks were also criticized. Rooms are typically shared by at least eight adults, but at Zhengzhou the report found that as many as 20 to 30 workers would squeeze into three-bedroom "apartments" fitted with two-level beds. Conflict among roommates in these confines was not unusual, the report said. The use of appliances deemed "high energy," such as kettles and laptop computers, was also prohibited.
A statement obtained by CNN from Foxconn in response to the report said: "While we have not seen the report in question, the welfare of our employees is without a doubt our top priority and we are working hard to give our more than one million employees in China a safe and positive working environment.
"To that end, earlier this year, Foxconn Technology Group welcomed the audit of three of our campus operations by the Fair Labor Association (FLA) because they support our company's process of continuous improvement in our workplace policies and practices. This review is the largest and most comprehensive assessment of an electronics manufacturing operation ever undertaken by any independent audit organization in China and we are proud to be a part of such an important initiative.
"Foxconn has participated fully and openly in this review and we are working closely with the FLA to carry out a remediation program to continuously improve the working environment for our employees and to ensure they are treated with respect. This is in addition to the policies and programs we have instituted over the last two years to ensure that our workers in China have the support they need to deal with challenges they face inside and outside the workplace.
"Our success and commitment to our employees will be judged by future FLA audits and the monitoring of the implementation of the remediation program, by reviews carried out by our customers and by future employee surveys. Our employees are our greatest asset and we are fully committed to ensuring that they have a safe, satisfactory and healthy working environment."
The FLA's audit of Apple's final assembly suppliers in February -- requested by Apple itself -- revealed that Foxconn violated standards in working hours and compensation.
"The key issue is the hours of work," FLA CEO Auret Van Heerden told CNN. "We found that Foxconn had worked beyond code limits of 60 hours per week, and beyond Chinese legal limits of 49 hours per week during peak periods."
The FLA said Foxconn accepted the findings and would implement the necessary changes.
Meanwhile, Apple also released a statement in response to Thursday's SACOM report.
"We care about every worker in our worldwide supply chain. We insist that our suppliers provide safe working conditions, treat workers with dignity and respect, and use environmentally responsible manufacturing processes wherever Apple products are made. Our suppliers must live up to these requirements if they want to keep doing business with Apple."
In February, CEO Tim Cook announced that Apple would start releasing data on working hours monthly as it seeks to end the industry practice of excessive overtime. The California-based technology giant told CNN they are now monitoring compliance among suppliers for over 800,000 workers.
For April, Apple said its suppliers achieved 95% compliance to the 60-hour work week specified in its code -- up from 91% in March even as it ramped up production of the new iPad.
CNN's Sarita Harilela contributed to this report.