Foxconn is a Shenzhen-based thriving tech firm linked to Taiwan electronics giant Hon Hai Group, as well as a major manufacturer for US-based Apple Corp.

In its Longhua manufacturing base in Shenzhen, Foxconn employs more than 300,000 workers. Its total employees in Shenzhen reach 420,000.

Foxconn headquarter building. [File photo]

In a Saturday interview with China Central Television (CCTV), an ex-employee of the company surnamed Zhang said Foxconn was a place where "one cannot make money without working overtime".

"It was tiring working there. We often worked into midnights and took over 100 extra shifts each month," Zhang said, adding he quit after two years because of the tremendous workload.

"The basic pay is about 900 yuan ($132) a month. Workers usually get 1,800 yuan, where all the extra is overtime payment," he said.

Another ex-employee surnamed Jiao said it was common for supervisors to criticize workers who didn't indulge in overtime.

"It made me feel uncomfortable," he added.

The company has never confirmed any connection between its employees' deaths and the work pressure or its management models.

Instead, it often blamed the "immature mentality" of the post-80s and post-90s (people born between 1980 and 1999) generation, who form the majority of the company's production line.

All the seven dead in the Foxconn suicides were aged between 18 and 24.

Xu Kaiwen, a PhD with the center for psychological heath and consultation at Peking University, said this particular generation was facing a common problem.

"To bring it up to a broad level, I think they possibly lack idealities and value concepts," Xu said.

On May 11, a 24-year-old Foxconn employee, Zhu Chenling, killed herself by jumping off a rented apartment in Shenzhen.

Responding to Zhu's suicide then, Foxconn spokesperson Liu Kun said the company had set up "an effective and non-gratuitous information system where employees could inform supervisors about their colleagues' emotional problems", with a bonus involved for the informers.

"Just last month, we've successfully prevented more than 20 possible suicides," Liu said.

Earlier this month, company officials were reportedly inviting monks to conduct a religious rite to dispel misfortune, in the hope of "releasing nervous emotions of employees".