Beijing's Communist Party leadership has issued repeated warnings that legions of idle rural workers gathered in the country's struggling export hubs could pose a threat to the social stability.
Clashes between police and unpaid workers locked out of failed factories have flared up across China in recent months, but the government bans independent trade unions, depriving workers of a key channel for resolving disputes.
Sun Chunlan, vice-chairman of the state-backed All-China Federation of Trade Unions, said police taskforces had been "rushed" to all regions to "understand the situation with regional social stability," the Beijing News paraphrased him as saying during a teleconference with officials.
Authorities needed to guard against "hostile forces within and outside China using the difficulties of some enterprises to infiltrate and bring trouble to rural migrant workers," Sun said. He did not elaborate.
After enacting a landmark labor law last year giving greater protection to the country's 130 million migrant workers, labor rights groups have accused officials of turning a blind eye to violations amid economic hardship to help factory owners survive the financial crisis.
Sun said China's official trade unions would extend aid to more than 10 million migrant workers, in the form of job training or "living assistance."
But about 20 million jobs alone have been lost in Guangdong province, southern China's manufacturing hub where a third of the country's exports are produced, an official from China's top planning agency said on Tuesday.
In Dongguan, one of China's largest factory belts in the Pearl River Delta, the labor market on the ground remained tight for many returning migrant workers.
Workers in Changping, a mid-sized industrial town, congregated outside factory gates ahead of recruitment drives and massed on street corners where ad-hoc job recruiters with foldable tables touted work.
"A lot of factories are looking for workers but they're mainly looking for skilled employees or women," said Yang Yun, a jobless 25-year-old from southwestern Guizhou province walking alone along a dusty avenue carrying all his possessions.
Other workers said the situation was not yet desperate, but many were lowering wage expectations to under 1,000 yuan ($145) a month, hoping to make up the shortfall with more overtime.
A senior Guangdong police official on Tuesday warned of a "grim" public security outlook in the province bordering Hong Kong, warning that ranks of jobless workers could be "tempted by crime and become a factor of instability."
Police in neighboring Fujian province shot two robbery suspects, killing one, after they resisted arrest and injured five policemen during a raid, Xinhua news agency said in a separate report.
The two were among nine members of a gang that carried out armed robberies at construction sites across Fujian 's Quanzhou city, injuring dozens and stealing more than 1 million yuan ($146,000), the agency said, citing police.
(Additional reporting by James Pomfret; Editing by Nick Macfie)