According to employees at the big four accounting firms, PwC, KPMG, Ernst & Young and Deloitte Touche Tohmatsu Limited, a newly-recruited university graduate can expect to earn 5,000 yuan ($769) to 6,000 yuan a month. Their monthly salaries can often double or triple after a few years.

Many big four workers admit that their companies are known for paying well, but they are also notorious for overworking employees at the same time.

"Working overtime is normal at the big four. It's like a culture," said a junior auditor at Ernst & Young, who declined to be identified.

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"They will give you a project and set a deadline, but it's impossible to finish it without working overtime," she said.

In order to finish her projects, she usually works at least 20 extra hours every week. January to April is the busiest period for the company, and during that time she often works until midnight and has only one day or even a half-day off a week.

"Taxis queue up for us in front of our office building at midnight," she said.

Experts said both employers and employees should attach great importance to the adverse effect that overwork brings.

Companies should hire more workers to share the heavy workload rather than hire inadequate numbers in order to reduce labor costs and force them to overwork, said Feng at 51job Inc.

"Employees, especially those born after the start of the 1980s, often lack the ability to take care of themselves. If any physical or mental problem occurs during work, they should take it seriously," she said.

Tang Ningyu, professor of the School of Management at Shanghai Jiao Tong University, said employers should make a great effort to help their employees to strike a proper balance between work and home.

"Companies should ensure better employee welfare, provide regular health examinations and force employees to take holidays," said Tang.

If employees achieve a better work-life balance, it will have a positive effect not only on the individual career paths but also on the development of companies, she added.

Li Wen, a Beijing lawyer, said labor unions could play a role in protecting employees from overwork.

But the fact is that, currently, many Chinese offices of international companies, including the big four, do not have labor unions, said Li.