China's top trade union organization will prioritize setting up unions in all overseas-funded businesses that have been operating in the country for more than five years, particularly the world's four-biggest audit firms, which have a strong presence in China.

Of the roughly 200,000 foreign-funded corporations in China, 91.4 percent had union representative by the end of 2012, said Wang Ying, a deputy chief overseeing grassroots labor organizations in the All-China Federation of Trade Unions.

"There are still enterprises that have invested in China for many years but are still reluctant to set up unions," she said, highlighting particularly the ‘Big Four' audit companies of PricewaterhouseCoopers, Deloitte Touche Tohmatsu Ltd, Ernst & Young, and KPMG, which together employ nearly 40,000 people nationwide.

"Those companies have often resorted to excuses that a union would encourage employees to raise demanding work-related requests.

"They have always delayed the establishment of unions because they lack a full understanding about the function of a Chinese union," she said.

Another factor that has dampened enthusiasm to set up a union is that the Trade Union Law requires corporations to contribute the equivalent of 2 percent of workers' total monthly wages as union funds, according to Wang.

"They worry that establishing a union will increase their costs."

Wang said that China's union rules generally require corporate unions to keep 60 to 70 percent of their funds for union management and activities, and the rest goes to higher-level union organizations.

"All corporations in China should obey Chinese laws, and they should also understand that in China the primary task of a union is to help enterprises develop and boost collective contract agreements and to mediate labor relations through negotiation between employees and employer," she said.

Chinese law allows 40 regular hours plus nine hours of overtime per week, but Wang said that it had been reported to her that employees at the "Big Four" are forced to work a lot more overtime, and that stress levels were huge.

"A union would help them better guard their legitimate rights," she added.

"We will fully comply with government requirements in this matter," said a statement Ernst & Young sent to China Daily on Thursday.

An employee at KPMG's Beijing office told China Daily that she would welcome possible union representation.

"It would be good news if a union could help us obtain higher overtime pay," she said, speaking on condition of anonymity.

The employee added that she works 13 hours a day at busy times, and 10 hours a day during slow periods.

Wang Ying said the Federation would be working to cooperate with the Chinese Institute of Certified Public Accountants on pushing for the establishment of unions at the "Big Four".

She added that she and her officials will continue to boost setting up township-level, regional and industrial union federations to cover smaller overseas-funded firms with employees fewer than 25.

Trade Union Law stipulates that a corporate unit with 25 employees or more should set up a union.

Many overseas-funded businesses and the people they employ have benefited from the representation of unions.

Germany's Bosch Rexroth Hydraulics and Automation Co Ltd in Beijing set up its trade union in 1996, and it has played a key role in holding collective wage talks since 2010.

Li Ming, the company's union chairman, said the new round of talks would be held in April or May with workers expecting a 5-percent year-on-year wage rise this year.