South Korea on Wednesday dismissed as "groundless" a North Korean diplomat's claim that South Korea and Malaysia are colluding in the process of a probe into the recent murder of the half brother of the North's leader Kim Jong-un.

"It is an unreasonable and groundless claim," a foreign ministry official said on condition of anonymity. "It is not even worth responding to. We know that the Malaysian government also clarified its position in a foreign minister's statement on this matter."

In a press conference on Monday, Kang Chol, North Korean top envoy to Kuala Lumpur, said that he cannot believe the results of the investigation done by Malaysian police into the killing of Kim Jong-nam and claimed that South Korea must have colluded with the Southeast Asian country in his death.

Kim Jong-nam, the eldest son of late former leader Kim Jong-il, died last week in an airport in Malaysia after being attacked by two Asian women with what appears to be poisonous substances. He was waiting for a flight to Macau where his residence is located.

Malaysian police have arrested four in connection with the murder case including Ri Jong-chol, a 46-year-old North Korean man and two Asian women. They said they are looking for four more North Koreans who fled Malaysia on the day of Kim's death.

In response to Kang's claim that South Korea and Malaysia are colluding in the ongoing investigation, Malaysia's foreign ministry said in a statement earlier in the week that Kuala Lumpur viewed the comments as "baseless." (Yonhap)