BEIJING - Grassroots authorities have been told to improve their handling of labor disputes to ensure the country's 240 million migrant workers are paid in time for the lunar new year.

Chunjie, or Spring Festival, is the time when most low-paid laborers collect their wages and head back to their families in the countryside.

However, a recent survey by an NGO affiliated with Peking University showed that 41.2 percent of construction workers have at some point seen their payment delayed - sometimes indefinitely.

This year, due to slow economic growth, the problem could get even worse, experts say.

On Monday, local officials were ordered to ensure that all labor disputes involving more than 10 workers must be filed within a day and addressed within seven days.

The demand was jointly issued by nine ministerial-level agencies, including the National Development and Reform Commission, and the Ministry of Housing and Urban-Rural Development.

The government will take measures to protect the interests of migrant workers and avoid a rise in mass disputes, said Yin Weimin, minister of human resources and social security, at a meeting on Monday.

The NGO, which polled more than 1,000 migrant workers at 40 construction sites in Beijing, Shanghai, Shenzhen and Chongqing and released the report on Sunday, also found that more than 75 percent did not sign contracts with their employers.

Sun Kui, a lawyer at Beijing Anheng Law Firm who has handled hundreds of labor disputes, said most laborers have to work without contracts, or they would never get a job.

"Migrant workers are in a weaker position when dealing with companies," he said, adding that even if workers win a lawsuit against their bosses, they still might never see the money.

"Many construction companies are ghost businesses that use fake addresses on contracts," Sun said. "Such cases are very common."

Qi Chuanying, 53, has spent more than 18 months trying to get the 4,000 yuan ($630) he is owed by a company he worked for in Beijing.

"I spent more than 2,000 yuan on a lawyer who helped me win a lawsuit. However, I still couldn't get my pay, as the boss has gone into hiding," said the construction worker, who comes from Heze in East China's Shandong province.

Due the introduction of several tight fiscal policies, experts say this year could prove particularly rough for workers.

However, economist Feng Xiliang said slow economic growth is no excuse for delayed payment.

"It's not fair," the vice-president of Capital University of Economics and Business' School of Economic Relations said on Tuesday. "It will ruin the companies' reputation and no workers will want to work for them anymore."

Li Guoli, chairman of the labor union at First Harbor Engineering, which is affiliated with China Communications Construction Corp, said the company had to suspend projects in Shanxi province to avoid owing too much money to migrant workers.

About 200 laborers, who have worked for months to build railways in Linfen, Shanxi, were not paid in October and November, he said.

"Our company is trying its best to satisfy the needs of its workers," Li said, adding that the firm has promised to pay all salaries before Spring Festival.

Jin Huiyu contributed to this story.