Denuclearisation will be high on the agenda for this week's inter-Korean summit in Pyongyang, South Korean President Moon Jae-in said yesterday on the eve of his third meeting with North Korean leader Kim Jong Un.

Moon will fly to the North Korean capital today for the latest stage in a diplomatic thaw on the peninsula, although progress has stalled in denuclearisation talks between Pyongyang and Washington.

"I've confirmed the sincere willingness of both Chairman Kim Jong Un and President Trump on several occasions," Moon said during a Cabinet meeting.

"I plan to hold frank talks with Chairman Kim Jong Un on ways to find a point of compromise between the US demand for denuclearisation and the North's demand for ending hostile relations," he added.

Moon, who met Kim in April and May this year, was instrumental in brokering the historic Singapore summit between US President Donald Trump and Kim in June, when Kim backed denuclearisation of the "Korean peninsula".

But no details were agreed and Washington and Pyongyang have sparred since over what that means and how it will be achieved.

The US is pressing for the North's "final, fully verified denuclearisation", while Pyongyang is seeking a formal declaration that the 1950-53 Korean War is over -- hostilities ceased with an armistice rather than a peace treaty. It has condemned demands for it to give up its weapons unilaterally as "gangster-like".

The dovish South Korean leader -- who has gladly taken on the role of a mediator -- will try to close the gap between the US and the North, according to Moon's chief of staff Im Jong-seok.

"Through various meetings and phone calls, President Moon has a better understanding of what the US is thinking than Chairman Kim," Im told reporters.

Moon is due to fly to New York later this month to attend the UN General Assembly, where he is expected to meet Trump.

Moon will hold at least two formal meetings with Kim, who may make a rare appearance at the airport to welcome his guests, the chief of staff said.

The South's president is also scheduled to attend a concert and visit key sites in the North's capital with his delegation, which includes tycoons Lee Jae-yong -- the heir to the Samsung group -- and the vice chairman of Hyundai Motor.

Moon has been pushing inter-Korean economic co-operation but several South Korean newspapers urged caution yesterday, with the Korea Herald calling the businessmen's presence on the trip "untimely".