HONG KONG • Police in southern China have arrested at least three workers' rights leaders in recent days, according to labour groups and activists.

The detentions come amid rising labour unrest in southern China, one of the world's most important manufacturing centres, and are prompting concern that the Communist Party is extending its latest crackdown on civil society to a new arena.

Mr Zeng Feiyang, director of the Panyu Workers' Centre in the city of Guangzhou, was put under criminal detention last Friday on charges of "gathering a crowd to disturb social order", said the Hong Kong-based non-profit group China Labour Bulletin and several labour activists. Ms Zhu Xiaomei, a labour organiser, was also detained, as was Mr He Xiaobo, who runs a group in Foshan that helps injured workers.

Mr Zeng is a lawyer and prominent labour organiser. His non-governmental organisation helps workers negotiate pay and benefits.

Although China restricts the formation of independent labour unions, thousands of workers have nevertheless organised and often gone on strike.

With many factories moving to regions where lower wages prevail - or to other countries such as Vietnam - labour unrest is rising, said Mr Geoffrey Crothall, a spokesman for the China Labour Bulletin, which promotes independent labour unions in China and tracks labour protests.

According to the group, the number of strikes and protests in Guangdong has more than doubled this year, rising to 56 last month from 23 in July.

"They don't know how to respond," Mr Crothall said. "And the only solution they can come up with is by cracking down on the people who are actually trying to help."

A Chinese labour researcher, who asked not to be identified, said that at least 16 activists had been detained, questioned or had disappeared. "They want to make an example of them for workers' rights' defence in the future - don't get involved with these labour organisations."

NEW YORK TIMES