South Korea has failed to persuade the North to attend talks with its neighbours and the United States to resolve the dispute over its nuclear weapons programme.
The North is thought to have stored 8,000 spent fuel rods
Delegations from the two Koreas, meeting in the southern capital Seoul, did agree to seek a peaceful solution through "appropriate" dialogue.
North Korea has long insisted on first having bilateral discussions with the US before wider talks involving China and Japan as it blames Washington for provoking the crisis over its weapons programmes.
At the meeting, which went on through Friday night, the two Koreas also agreed to arrange another reunion of families separated since the Korean War 50 years ago and hold economic co-operation talks in Seoul next month.
However the BBC's Charles Scanlon in Seoul says there is a growing sense of urgency in the region amid fears that the nuclear dispute is entering a more dangerous phase.
South Korean intelligence said last week that the North had reprocessed some spent nuclear fuel rods to create weapons grade plutonium.
The US also appears to be preparing the ground for the interception of North Korean ships thought to be carrying illicit cargo, our correspondent says.
The nuclear crisis erupted last year when the US disclosed that North Korea had admitted developing nuclear weapons in violation of an international accord.