An index that shows the current performance of small and medium-sized enterprises - the part that offers the most jobs in China - fell to 55.6 in January from 56.6 in December, according to data provided by Standard Chartered Bank. It points to weaker growth as sluggish demand continues to weigh on production.

According to the National Bureau of Statistics, the total number of rural migrant workers was 273.95 million in 2014, up 1.9 percent from a year earlier. The growth rate was 2.4 percent in 2013 and 3.9 percent in 2012.

Yang Junxiong, an official from the NBS, said that the growth rate of migrant workers has slowed down.

"As more rural migrant workers get permanent residence in cities, the surplus of rural workers will decrease, and labor costs will keep increasing."

A shortage of workers would be a major drag for the economy in the near future, said Yang.