South Korean President Moon Jae-in will send a team of special envoys -- including Seoul's spy chief -- to the North tomorrow to push for talks between Washington and Pyongyang on nuclear weapons.

The delegation, announced by Moon's office on Sunday, is the latest chapter in a remarkable Olympics-driven detente between the two Koreas.

An intense rapprochement saw the two foes march together at the South's Pyeongchang Winter Olympics that ended February 25, with the North's leader Kim Jong Un sending his sister as a special envoy to the event.

Kim Yo Jong's appearance at the Games' opening ceremony made global headlines, marking the first visit to the South by a member of the Kim family since the end of the Korean war.

Moon has sought to use the Pyeongchang Games to open dialogue between the US and the North in the hopes of easing a nuclear standoff that has heightened fears over global security.

He chose five top officials -- including top national security advisor Chung Eui-yong and spy chief Suh Hoon -- to visit Pyongyang on Monday, Moon's spokesman said.

"The special delegates will have extensive discussions over issues including creating conditions for North-US talks to denuclearise the Korean peninsula and improving inter-Korea ties," Yoon Young-chan told reporters.

The 10-member group -- five top delegates and five supporting officials -- would fly to the North's capital Pyongyang tomorrow afternoon before returning on Tuesday, Yoon said.

The delegation will then fly to the US to explain the result of the talks to officials in Washington, he added.

Suh is a veteran in dealings with the North. He is known to have been deeply involved in negotiations to arrange two previous inter-Korea summits in 2000 and 2007.

The isolated, impoverished North staged its most powerful nuclear test and test-fired multiple missiles last year, including some capable of hitting the US mainland, in defiance of UN sanctions.

The North's leader Kim and US President Donald Trump have also traded threats of war and personal insults, sending tensions soaring.

Moon, who advocates dialogue with the 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.

On Saturday, a foreign ministry spokesman in Pyongyang called on the US drop any preconditions for talks.

"The US is taking preposterous action by continuing to trumpet an insistence that it will not have dialogue unless a right condition is met," the unnamed spokesman was quoted as saying by the state-run KCNA news agency.