Darusman traveled to South Korea Wednesday as part of a three-day fact-finding mission.
"I will use this fact-finding mission to Seoul to better understand any aspects or factors that may impact on inter-Korean relations," he said in a statement Monday. "Such issues can affect a wide range of human rights, such as the reunification of the hundreds and thousands of separated families on the Korean Peninsula."
The U.N. Human Rights Council in March set up a commission with a one-year mandate to investigate North Korean rights issues. Darusman is part of that commission, which is tasked with investigating violations related to torture, arbitrary detention, the right to life, enforced disappearances and the right to food, among other things.
Darusman said he regrets he's been unable to visit North Korea despite repeated requests.