Drug-associated crime has been the most frequent reason for the imprisonment of North Korea defectors in South Korea so far this year, a parliamentary report showed Wednesday.

A total of 129 North Korean defectors were behind bars in South Korea as of Aug. 26, compared with 51 recorded in 2011, the report released by Rep. Kang Chang-il of the main opposition Minjoo Party of Korea showed.

Of the 129 imprisoned, 38 were convicted of drug-related crimes while 15 others were guilty of violence, according to the report. 

Other main offenses included fraud and murder, the report also showed.

A majority of 111 prisoners out of the total 129 defector convicts behind bars were male, a growth of 136 percent from 2011.

Only 18 prisoners were women, but the number marks an increase of 350 percent from 2011 when only 4 female North Korean defectors were in prison, it said.

"Under the burden of livelihood difficulties and homesickness, more defectors tend to get involved in crimes with the number of defector prisoners on the rise," Kang said. "There's pressing need for a system that consistently provides crime prevention education and job consulting to defectors, especially as the population of North Korean defectors in South Korea is nearing 30,000." (Yonhap)