Poor working conditions and long working days at an iPhone factory in China have once again brought the plight of the workers to light in a BBC documentary, according to The New York Times.

Undercover BBC reporters found that despite having rules for work hours, they are routinely broken. Factories on on the outskirts of Shangai run by Pegatron, a supplier that assembles iPhones and iPads, were investigated.

The documentary highlighted a number of abuses ranging from the long working days, to denials for time off and even included observations of child labor.

The BBC reporters said despite rules limiting workers to 60-hour weeks, one had worked 18 days in a row while another worked a 16-hour shift. One reporter's ID card had been stolen by a manager.

They also reported seeing children working in tin mines in Indonesia.

Apple is the latest among major tech companies whose Chinese factories have been cited for abuse of and poor conditions for workers.

Following the release of the documentary, Jeff Williams, Apple's senior vice president for operations, sent an email to employees in Britain stating that they were offended by the conclusions of the BBC documentary.

Williams also said Apple suppliers were 93 percent compliant with the 60-hour week requirement but admitted the company could improve.

"Several years ago, the vast majority of workers in our supply chain worked in excess of 60 hours, and 70-plus hour work weeks were typical. After years of slow progress and industry excuses, Apple decided to attack the problem by tracking the weekly hours of over one million workers, driving corrective actions with our suppliers and publishing the results on our website monthly -- something no other company had ever done," Williams said.

But no officials from Apple have released a statement publicly about the documentary.