Bilateral talks to draft a nuclear deterrence plan by the end of 2013 have been under way since last year, but the North's third nuclear test on Monday increased the urgency to complete the plan, Yonhap News Agency reported Wednesday.
The Feb. 21 meting in Washington will discuss sharing intelligence so signs of a nuclear attack can be detected early.
Military officials said rules would be set for pre-emptive measures in the event of North Korean provocations.
South Korean Deputy Defense Minister Lim Kwan-bin and Mark Lippert, U.S. assistant defense secretary for Asian and Pacific security affairs, will attend.
Defense Minister Kim Kwan-jin told the South Korean parliament Tuesday the best option in case of an imminent attack was destroying Pyongyang's nuclear facilities.
Critics cautioned against such an attack, saying it was uncertain whether all of the communist country's nuclear capabilities would be eliminated because clandestine facilities are believed to be scattered around the country.
Military officials are also concerned about North Korea's ability to launch missiles from mobile platforms that cannot be easily detected by satellites.