The pilot projects were carried out in 10 regions including Beijing. The Beijing Federations of Trade Union (BFTU) is planning to boost the independence of the chairman of trade unions by paying them from a special fund.

"The chairmen of trade unions at the primary level are paid by enterprises. If you are not obedient, the enterprise could break the contract with you," a chief at BFTU told the Global Times Monday, adding that this conflict of interest makes it difficult for them to help workers, especially at private firms.

Su said other issues must be addressed. "It is very likely that enterprises could bribe the trade union chief to speak for the company's interest."

He suggested that the leader of a trade union should be paid through fees collected from workers in order to foster a stronger sense of independence.

Sherry Yan, assistant professor of economics at the New Jersey Institute of Technology, argued that China should learn from western labor unions.

For example, most union chiefs in the US are paid from fees collected from workers and many leaders don't work for the enterprises but just workers.

Feng Yujun, a law professor at Peking University, said most migrant workers are not educated and face a disadvantage during labor disputes.

On July 6, BFTU announced that a collective bargaining system would be created in 10 key regions and industries.