North Korean workers rest on a river bank near Dandong in China's Liaoning Province (file photo). /AP-Yonhap

Half the North Korean visitors to China went there to work, and there are already 30 percent more of them this year than in 2010.

Voice of America on Wednesday said that 110,000 North Koreans officially visited China in the first nine months of this year, according to Chinese government statistics, 31 percent more than the whole of last year.

A total of 55,000 said they came to China for work, up 42 percent from last year. Others cited reasons such as "to attend conferences or do business" and "to travel or see relatives."

Some 95,000 were men and 15,000 women.