South Korean President Moon Jae-in will discuss ways to denuclearize the Korean Peninsula when he meets North Korean leader Kim Jong-un this week, Moon's chief of staff said Monday.

Im Jong-seok said it will mark a rare opportunity to discuss the issue with the North Korean leader himself.

"Just until recently, denuclearization had been an agenda item for talks between the North and the United States," Im told a press conference in Seoul, one day before the South Korean president was set to embark on a three-day trip to North Korea.

"Now, denuclearization is a key issue (at the inter-Korean summit)," Im said.

"This issue cannot be discussed at the working level and even if it is discussed (at the working level), no agreement can emerge from such talks," he added, highlighting the importance of talks on the issue between the leaders.

Moon will have at least two occasions to discuss ways to denuclearize the Korean Peninsula with the North Korean leader, Im noted.

The South Korean president will head to Pyongyang at 8:40 a.m., using a direct flight from Seoul's Seongnam Air Base.

He is scheduled to arrive in the North Korean capital at 10:00 a.m.

His first meeting with Kim will be held later Tuesday, followed by an official welcome dinner that could possibly be hosted by Kim.

Moon and Kim will hold their second meeting on Wednesday, according to Im.

The presidential chief of staff said Moon's North Korea trip will focus on three agenda items.

The first is to improve and develop inter-Korean relations and the second is to mediate and promote North Korea-US talks for denuclearization of the Korean Peninsula, Im said. Thirdly, they will discuss reducing military tensions and ending the threat of war, he added.

Moon's trip to Pyongyang comes amid an apparent deadlock in the US-North Korea denuclearization talks.

Washington insists on the need for maximum sanctions and pressure against the North until the communist state fully denuclearizes while Pyongyang is said to be asking for early rewards for the steps it has taken so far.

 Whether the South Korean president will succeed in convincing the North Korean leader to restart his country's denuclearization process remains to be seen, Im noted.

"There are many expectations for great progress on the issue at the summit, but (the possibility) is very limited," he told the press conference.

"Whether an agreement on specific ways to progress denuclearization will emerge, and if such an agreement will be put into a document or be announced orally, all these things are still blank to us," he added, stressing the importance of "frank discussions" between the two leaders.

Moon is currently scheduled to depart Pyongyang early Thursday, but his departure may be pushed back, apparently pending on the outcome of his talks with the North Korean leader, according to Im, who said the leaders may decide to hold a currently unscheduled event aimed at enhancing their personal relationship.

Part of the inter-Korean summit in Pyongyang will be broadcast live in Seoul, marking the first time in history for any event in the communist state to be broadcast live in South Korea, Im noted.

The Moon-Kim summit will mark the third of its kind since Moon took office in May 2017. The two leaders held their first two meetings on April 27 and May 26 in the border village of Panmunjom that sits directly on the inter-Korean border. (Yonhap)