Smoke and debris rise in the air as an observation post next to the entrance of the north tunnel of North Korea's nuclear test site at Punggye-ri, North Hamgyong Province, is blown up in this May 24, 2018 file photo. Korea Times file

South Korea plans to conduct radiation exposure tests on 89 North Korean defectors who hailed from areas near the North's Punggye-ri nuclear testing site, Seoul's unification ministry said Thursday.

The radiation testing will be carried out starting in May for six months on North Korean defectors who had lived in Kilju County and its nearby areas, and escaped the North after its first nuclear test in 2006, according to the ministry.

The government previously held such similar tests on 40 North Korean defectors in 2017 and 2018.

"It is meaningful to preemptively check the possibility of exposure to radioactive leaks and overall health conditions for those who may have sustained damage from the North's nuclear tests," a ministry official told reporters.

The North's Punggye-ri nuclear test site is located in Kilju County in the country's northeastern province. The secretive regime has conducted all six of its nuclear tests at the site.

Among the 89 defectors to undergo the testing, nine will be those who were suspected of having been exposed to radiation during the government's previous tests. The ministry will select the 80 others out of a group of those hoping to be tested.

In total, 796 North Koreans who used to live in areas near Punggye-ri defected to the South in the wake of the North's first nuclear detonation in October 2006.

In a report released in February, the Transitional Justice Working Group, an advocacy group for the North's human rights, said hundreds of thousands of residents living in the area near the Punggye-ri site are at risk of exposure to radioactive materials being spread by underground water. (Yonhap)