Apple's chief executive Tim Cook has vowed to dig deeper into complaints about its factories in China having harsh and poor working conditions to manufacture iPhones, iPads and computers.

In an email reportedly sent to Apple's 60,000 employees, Cook, said Apple would "continue to dig deeper" into problems in China and would "undoubtedly find more issues".

"What we will not do, and never have done, is stand still or turn a blind eye to problems in our supply chain," Cook said in the letter that was reproduced on the website 9to5mac.com.

"Any accident is deeply troubling, and any issue with working conditions is a cause for concern. Any suggestion that we don't care is patently false and offensive to us. As you know better than anyone, accusations like these are contrary to our values. It's not who we are," he added.

The letter appears to be in response to a series of articles appearing in the New York Times that highlighted the company's problems in China and on reports of divisions within Apple about how to handle these issues, The Telegraph reports.

The paper said over half of the suppliers audited by Apple have broken at least one part of the company's conduct code each year since 2007, and some have even broken the law in some cases.

The NYT report claimed that Apple relies on child labour 24 hour days and promotes unsafe conditions to manufacture its products. (ANI)