The Ministry of Public Safety and Security, to be officially launched on Wednesday, will oversee the response to all future land and sea disasters.
A major ministry with more than 10,000 staff, it will take over responsibilities previously shared by a number of state units, including the national coastguard which was disbanded in the wake of the Sewol tragedy.
Former admiral Park In-Yong will lead the new body, while ex-army general Lee Song-Ho has been appointed vice minister, the presidential Blue House announced.
Lee was credited with leading a successful mission in 2011 to rescue 21 sailors aboard a South Korean freighter hijacked by Somali pirates.
The 6,825-tonne Sewol was carrying 476 people when it capsized and sank on April 16 off the southern coast. Of the 304 who died, 250 were high school students on a school trip.
The official response to the disaster was widely criticised for being slow, uncoordinated and unfocused, and prompted President Park Geun-Hye to vow a complete overhaul of national safety standards.