Over-supply of labor in China's vast rural areas will continue now and for years to come, as China's migrant workers numbered about 230 million in 2009, Vice Minister of Agriculture Wei Chao'an said Wednesday.

Wei told a press conference on the sidelines of the ongoing annual session of the National People's Congress (NPC), China's parliament, that he saw contradictions between current reports about "labor shortage" in coastal cities and massive underemployment in rural areas.

"We need further analysis on the reported 'labor shortage'," he said. "On the one hand, it is difficult for enterprises in coastal areas to recruit enough workers this year. And on the other hand, it is difficult for the countryside to transfer its redundant laborers to cities for employment."

The vice minister noted that over-supply of labor and underemployment would remain a challenge for China in the much longer term with its huge number of rural labor force.

Wei quoted the National Bureau of Statistics as saying that China had about 230 million farmer-turned workers last year, of whom about 145 million were seeking job opportunities outside their hometowns.

The number of redundant laborers in rural areas totaled about 90 million in China, home to a population of more than 1.3 billion.

In the government report submitted last week to the NPC, Chinese Premier Wen Jiabao vowed to keep the urban registered unemployment rate no higher than 4.6 percent this year while guiding workers in an orderly flow, especially rural migrant workers.