A North Korean defector has been arrested by South Korean police after she arranged for 130 tonnes of rice to be sent across the Chinese border to Pyongyang, local media reports.

The 49-year-old woman, who has not been identified, is accused of breaking National Security Law after she sent two consignments of rice to the North Korea State Security Ministry using the help of a Chinese broker. She is also charged with providing material assistance to authorities in Pyongyang and attempting to return to the country, both illegal under South Korean law.

The two 65 tonne shipments are believed to worth 105 million won ($98,700) each, according the Security Investigative Service of the Gyeonggi Southern District Police. The woman is also charged with attempting to arrange a second deal with a broker worth 80 million won (US$75,200) before her arrest in Suwon on February 18.

The woman defected to South Korea in 2011 but is understood to have become disillusioned with life there and wishes to be reunited with her son. South Korean law does not permit the return of North Korean defectors to the country, also known as "double defectors."

According to her deposition, the woman has been in touch with Pyongyang's State Security Ministry since early last year and sent the rice as a pledge of allegiance to North Korean authorities. It is believed she raised the money lawfully through a business that she ran in Gyeonggi Province. She also arranged for her home and personal belongings to be sold in preparation for her return.

An estimated 30,000 North Koreans have defected across the border since the end of the Korean War in 1953.

However, it is rare for North Koreans to request repatriation. It was reported in 2015 that 700 North Korean defectors remain unaccounted for, with many having fled to China or Southeast Asia in the hope of arranging their return.

Earlier this month, defector Kim Ryen Hui staged a protest at the border by waving a united Korean peninsula flag and demanded that she be allowed return home to North Korea.

"I can make a living and it is no problem living here. I could be in a worse situation and may starve (in the North). But you cannot trade your family for anything," Kim told The Korea Herald.