North Korean workers gather after lunch at the Hong Chao Zhi Yi garment factory in Hunchun, Jilin province, China, Sept. 30, 2017. AP-Yonhap

North Korean workers have refused to go to work in the Chinese border city of Dandong, demanding their return to North Korea, a Seoul expert claimed Thursday.

Citing a source, Cho Han-bum, a senior research fellow at the state-run Korea Institute for National Unification, said on his YouTube channel that scores of North Korean workers staged a work stoppage in mid-February.

"North Korea dispatched its consul to the site right after the incident to handle the case, but is believed to have faced difficulties," Cho said.

"The workers are believed to be remaining stubborn, saying that even if they die, they will go home and die there," he said, adding that the workers are physically and emotionally exhausted amid protracted stays in China.

South Korea's spy agency said it is closely watching related developments as various incidents have occurred due to North Korean workers' dire living conditions.

Around 2,000 North Korean workers, dispatched by a trade firm under the North's defense ministry, occupied a factory in Helong, in China's Jilin Province, in January and staged a riot due to overdue wages, according to the Japanese daily Yomiuri Shimbun.

North Korea has been dispatching workers abroad, mainly to Russia and China, to earn much-needed foreign currency, in violation of United Nations Security Council resolutions on Pyongyang's nuclear and missile programs. (Yonhap)