Discontent among China's estimated 130 million strong migrant workers, who have helped power the country's growth, threatens to undermine the government's legitimacy and erode the nation's competitiveness as a low-cost factory hub.

Following are key developments from over the last month:

DENSO (GUANGZHOU NANSHA) CO LTD

A unit of Japan's Denso Corp resumed partial production after about one-third of its 1,200 workers returned to work on Thursday. The plant, which supplies fuel injection equipment and other parts, had stopped shipping to customers on Monday.

Worker representatives will meet management later to negotiate pay rises. Pay for most employees is 1,100 to 1,300 yuan ($162-$191) a month and they are demanding an increase to 1,900 yuan. Technicians are seeking a 1,000 yuan rise from their basic 3,000 a month salary, according to one Denso worker.

Toyota Motor Corp said it would resume production early next week at a Chinese auto assembly plant hit by the strike. Production had been suspended since Tuesday morning.

NHK-UNI SPRING (GUANGZHOU) CO LTD

A one-day strike at NHK-UNI Spring (Gungzhou) Co Ltd ended late on Wednesday. The plant, 60 percent-owned by Japan's NHK Spring and 40 percent by a Taiwanese firm, makes suspension springs and stabilisers for nearby assembly plants of Honda Motor Co Ltd, Toyota Motor Corp and Nissan Motor Co. Workers had been on strike since late on Tuesday.

Honda said production at a south China car plants, suspended due to the strike, restarted on Thursday. Media had reported a Nissan factory in Guangzhou suspended production briefly on Wednesday because of the walkout.

TOYODA GOSEI CO

Toyota's Tianjin factory, held jointly with Chinese carmaker FAW, resumed output on Monday after the strike-hit Toyota-affiliated parts maker Toyoda Gosei Co said it had reached an agreement with workers. Toyoda Gosei said workers had agreed to extra allowances for working in the summer heat and for a perfect attendance record on top of an original 20 percent wage increase.

NIHON PLAST

Honda affiliate Nihon Plast said on Monday it had settled a labour dispute with workers at its Zhongshan plant, which produces such plastic parts as steering wheels. The plant resumed production late last Friday after a strike the previous day.

CARLSBERG

Denmark's Carlsberg said a strike that began late last week at a brewery it part-owns in the southwestern city of Chongqing ended on Friday.

HONDA LOCK

Some 1,500 workers at Honda parts supplier Honda Lock, returned to work on June 15 after having walked off the job on June 9.

HONDA

Honda saw an unusually long work stoppage of three weeks at its wholly owned parts factory in Foshan when 1,900 workers downed tools demanding better pay. After violent clashes and a management move to hike pay by 24 percent, most returned to work on June 4.