South Korean prosecutors have arrested a senior security official of former President Moon Jae-in's administration over the handling of the death of a fisheries official two years ago.

Former National Security Adviser Suh Hoon was arrested on Saturday for suspected abuse of power.

Suh is suspected of having ordered security officials to delete intelligence reports that contradicted the conclusion that the official died trying to defect to North Korea, presented by Moon's administration.

The official, a crew member of a fishery inspection vessel, was fatally shot by North Korea's military in September 2020 in the Yellow Sea, west of the Korean Peninsula.

South Korean coast guard officials initially said he was planning to defect. But they retracted the comment in June this year, saying there was no evidence to suggest that.

South Korean media say prosecutors are investigating allegations that Moon's administration sought to cover up the incident to avoid a deterioration of ties with the North. There is speculation that Moon may also be subject to a probe depending on the outcome of the investigation of Suh.