The brother of a South Korean fisheries official killed by North Korea's military near the western sea border last year met with Unification Minister Lee In-young on Thursday and asked the government to deliver his letter to the North's leader.

Lee Rae-jin, the brother of the deceased official, said he handed Lee the letter, in which he asked for North Korean leader Kim Jong-un's cooperation so that he could visit the North to find the truth behind his brother's death.

"I asked the unification ministry to deliver my letter to Chairman Kim Jong-un," Lee told reporters after the meeting. "I don't know how North Korea will respond, but I am going to try my best."

Lee also urged the ministry to push ahead with a meeting with North Korean authorities and conduct a joint investigation with Pyongyang into the incident.

"I was told they're going to make sure such an incident won't happen again, but they said that other issues like holding a meeting with North Korean authorities, visiting the North and conducting the joint investigation all require a response from the North," he said.

In September last year, North Korea fatally shot the 47-year-old official, who was adrift on its side of the Yellow Sea, and burned his body, according to the South Korean military. He went missing the previous day while on duty near the western border island of Yeonpyeong.

His brother has sought a UN probe, raising strong doubts about the government's findings on the incident that the deceased official attempted to defect to the North.

Last year, he held separate meetings with the foreign minister and the defense minister to seek more information on his brother's death. (Yonhap)