Leaders of North and South Korea plan to sign a joint statement on inter-Korean relations after their summit on Wednesday in the North's capital Pyongyang, Seoul officials said.

North Korean leader Kim Jong Un and South Korean President Moon Jae-in will hold a joint news conference after the signing ceremony, and after the two Korea's defence chiefs adopt a separate military pact, Moon's press secretary Yoon Young-chan told reporters.

The content of the agreements was immediately not known.