"This move aims to make our services, in terms of protecting workers' rights, more accessible and to facilitate their supervision over us," he said.

"It will take time to promote the practice, but we hope that more than 70 percent of trade unions in our province will have introduced it by the end of the year."

There are more than 1.84 million trade unions nationally, with 226 million members, according to official figures published in 2010.

Feng Tongqing, a labor professor at the China Institute of Industrial Relations, welcomed the move.

"Many workers still don't know who they can turn to if they get into trouble or their rights are violated," he said. The trade union leadership is not well known among its members, he added.

"Workers have more diverse interests than before, and sometimes they differ from the company they work for. It is important that our labor unions can step in and mediate as an independent third party."

Feng was in wholehearted agreement concerning disclosure of union leaders' mobile phone numbers.

"Workers can run into difficulties anytime, and they may need to seek help during non-work hours, so our labor officials should guarantee that they will be contactable whenever needed," he stressed.

Li Fangping, a civil rights lawyer in Beijing, suggested that more representatives of workers should be invited to attend important union meetings and to participate in major events, including collective contract negotiation.