Police in China have formally charged a labour activist with disturbing public order, reports say, following one of the country's biggest strikes in years.

Lin Dong, who works at a labour dispute service, was charged with helping to organise protests, his colleague said.

Workers at the shoe factories in the southern city of Dongguan have been protesting for more than two weeks over their social security contributions.

The Taiwanese firm Yue Yuen makes shoes for brands like Nike and Reebok.

More than 40,000 workers in Dongguan, Guangdong province, had refused to report to work.

They had been pushing Yue Yuen's Taiwanese parent company, Pou Chen, for increased social benefits, compensation for overtime, housing benefits and a salary increase.

On Thursday, May 1 police detained Lin Dong and another activist, Zhang Zhiru, who was released a day later