North Korea's ceremonial leader Kim Yong-nam will visit South Korea this week as the head of the country's high-level delegation for the Winter Olympics, Seoul's Unification Ministry has said.

Mr Kim, who is president of the Presidium of the Supreme People's Assembly, will lead a 22-person delegation expected to arrive in South Korea on Friday for a three-day trip, the ministry said in a statement.

The Winter Olympics are scheduled to kick off on Friday and run through 25 February, during which Seoul hopes to hold high-level inter-Korean talks.

Mr Kim is North Korea's nominal head of state, while the country is ruled by Kim Jong-un, the third-generation hereditary leader.

The trip by Kim Yong-nam is set to be the diplomatic high point of the rapprochement between the two Koreas.

Tensions spiralled last year as North Korea carried out multiple weapons tests, including intercontinental ballistic missiles which it has said are capable of reaching the mainland United States.

For months, the country ignored Seoul's entreaties to take part in a "peace Olympics", until leader Kim Jong-un indicated his willingness to do so in his New Year speech.

That set off a rapid series of meetings which saw the two agree to march together in the opening ceremony and form a unified women's ice hockey team, their first for 27 years.

North Korea's Olympic participation would include a visit by a high-level delegation, they agreed.

The South Korean ministry did not explicitly say whether Mr Kim would attend the Pyeongchang opening ceremony.