China's registered urban unemployment rate was 4.2 percent in 2004, down 0.1 percent from 2003, the National Bureau of Statistics (NBS) said.

"This is the first decrease of unemployment rate in many years," NBS director Li Deshui acknowledged at a press conference Tuesday in Beijing, "however, it's difficult to say that China's unemployment rate will go on decreasing."

Controlling the unemployment rate is one of the four targets of China's macro-economic control, Li said.

The sound growth of China's economy and efforts by governments at various levels have ensured the drop in the unemployment rate last year, he added.

The newly added employees in urban areas reached 9.8 million, 800,000 more than expected, according to NBS statistics.

"It's still difficult to conclude that China's unemployment rate will continue to drop for numerous uncertain factors in economic growth in China as well as the whole world, including the slowdown of economic development, improvement of technology and population growth," he stressed.

He also noted the severe shortage of migrant workers appeared last year in the Pearl River Delta and the Yangtze River Delta. He attributed the shortage to the low salaries.

"With increased income of peasant farmers through better situation in rural areas, supply of migrant workers cannot be always unlimited if their salary in factories remains unchanged," he explained.

The average monthly salary in the Pearl River Delta has remained unchanged for decades and only about 600 yuan (73.7 US dollars) per month, according to the NBS's survey.

He urge the company bosses to raise the salary for migrant workers.