An intense rapprochement saw athletes from both sides of the divided peninsula march together at the South's Pyeongchang Winter Olympics last month, with the North's leader Kim Jong Un sending his sister as a special envoy to the event.

Kim Yo Jong's trip was the first visit to the South by a member of the North's ruling dynasty since the end of the Korean War, and her appearance at the Games' opening ceremony made global headlines.

South Korean President Moon Jae-in has sought to use the Pyeongchang Games to open dialogue between Washington and Pyongyang in the hopes of easing a nuclear standoff that has heightened fears over global security.

Kim Yo Jong invited him to a summit in Pyongyang on her brother's behalf, but Moon did not immediately accept, saying that the right conditions were necessary first.

"We plan to hold in-depth discussions for ways to continue not only inter-Korean talks but dialogue between North Korea and the international community including the United States," said national security advisor Chung Eui-yong, who is leading the delegation.

"We will deliver President Moon's firm resolution to denuclearise the Korean peninsula and to create sincere and lasting peace," Chung told reporters before his departure.

Chung is one of five senior officials who flew to Pyongyang on Monday.

It is the first ministerial-level South Korean visit to the North since December 2007, when Seoul's then intelligence chief travelled to Pyongyang.

Conservative Lee Myung-bak was elected the South's president the following day, and took a markedly harder line on relations with the North.

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Monday's delegation includes spy chief Suh Hoon, who is a veteran in dealings with the North. He is known to have been deeply involved in negotiations to arrange two previous inter-Korean summits in 2000 and 2007.

The North's official Korean Central News Agency also announced their impending visit in a one-paragraph dispatch.

The 10-member group -- five top delegates and five supporting officials -- will return to Seoul on Tuesday.

Other members include Suh's deputy at the National Intelligence Service as well as Chun Hae-sung, the vice minister of Seoul's unification ministry, which handles cross-border affairs.

The delegation will fly to the US on Wednesday to explain the result of the two-day trip to officials in Washington, according to the South's presidential office.

Last year, in defiance of UN sanctions, the isolated and impoverished North staged its most powerful nuclear test and test-fired several missiles, some of them capable of reaching the US mainland.

The North's leader Kim and US President Donald Trump traded threats of war and personal insults, sending tensions soaring before a thaw in the run-up to the Winter Olympics.

Moon, who advocates dialogue with the North's nuclear-armed regime, said last week that Washington needs to "lower the threshold for talks" with Pyongyang.

But the US has ruled out any possibility of talks before the North takes steps towards denuclearisation, and imposed what Trump hailed as the "toughest ever" sanctions on Kim's regime late last month.