Li left his farm in southwestern Sichuan Province more than 10 years ago and came to the capital to seek a better life. He was working at a construction site in Beijing's Fengtai District in April last year, but his employer refused to pay him, saying he was short of money.

Li felt lucky to be a success story for the showcase project "Enhancing Legal Aid Service for Migrant Workers in China" when other migrant workers were still owed back pay.

To help protect these workers' rights, 21 legal aid work stations have been set up nationwide to provide free legal assistance, including legal consultations and case presentation. The network is supposed to expand to all provincial capital cities and mid-sized cities.

These offices have also launched law awareness campaigns among migrant workers and distributed brochures encouraging them to seek legal aid to protect their rights.

As of the end of March, nearly 150,000 rural migrant workers had sought aid from such working stations, according to statistics from the China Legal Aid Foundation.

But those cases are just the tip of the iceberg, according to lawyer Shi Fumao, who works at the Beijing Legal Aid Working Station. In Shi's office, 16 lawyers worked day and night but still could not help all the migrants who had turned to them.

Migrant laborers, whose number is estimated at 210 million, have become a pillar of the country's work force, but they face problems that involve pay disputes, work injury compensation, health care and education of their children.

China now has no clear system to define who should bear responsibility when the rights of migrant workers are violated, said Shi, and thus these workers often didn't know where to turn for help.

"Although the awareness of legal rights among Chinese migrant workers has risen in recent years, it is still difficult for them to protect their rights," he said.

With so many rural people seeking employment, many are ready to waive their rights to get a job. For example, the labor law states that all employees should have contracts, but few migrant workers do. There's always someone hungrier for work who will take the job under any conditions.

Shi said his clients have usually been working without a contract or even a record of employment, which made it tough to collect legal evidence for court cases. It can take a year to resolve a suit against an employer, which is longer than many migrants have to wait.

Shi said that he remained optimistic, because both the government and the public were paying more attention to migrant workers' issues.

"The government has made sufficient laws to protect the rights of the migrants. The most important job now is to make the laws work," Shi said.

The Chinese government has vowed to ensure migrant workers get paid in full and on time, extend social security coverage to more of them and work out a suitable pension insurance system.

These points were included in the government work report Premier Wen Jiabao delivered at the opening of the First Session of the 11th National People's Congress, the country's top legislature, in early March.