The man who told US President Donald Trump that North Korean leader Kim Jong Un wanted to denuclearise was named as South Korea's foreign minister Wednesday, hours before the inauguration of Joe Biden.

Former national security adviser Chung Eui-yong will be responsible for Seoul's relations with treaty ally Washington after replacing UN veteran Kang Kyung-wha, who was Seoul's first female foreign minister when she was appointed in mid-2017.

Chung was instrumental in brokering the talks between Trump and Kim, which saw three headline-grabbing meetings between the two but little substantive progress.

In March 2018, after a year in which tensions soared as the two leaders exchanged mutual insults and threats of war, Chung visited Washington to brief Trump that Kim -- who he had met earlier in Pyongyang -- wanted to talk and was "committed to denuclearisation".

Former South Korean national security adviser Chung Eui-yong, who was instrumental in brokering US-North Korea talks, will become Seoul's new foreign minister
Former South Korean national security adviser Chung Eui-yong, who was instrumental in brokering US-North Korea talks, will become Seoul's new foreign minister KCNA VIA KNS / KCNA VIA KNS

An ecstatic Trump immediately accepted the request for a summit and Chung was deputised to make the announcement in an unorthodox night-time briefing on the White House lawn.

The two leaders met in a blaze of publicity in Singapore and signed a vaguely-worded statement on the denuclearisation of the Korean peninsula, but a second summit in Hanoi collapsed over sanctions relief and what the North would be willing to give up in return.

The process has been stalled ever since, while the North has showed off several new missiles at military parades in October and earlier this month, when Kim pledged to strengthen its nuclear arsenal.

South Korean President Moon Jae-in has long championed engagement with the North and his office said in a statement that Chung, 74, had been "involved in every issue in the US-South Korea relationship" and was the "best expert in the field of diplomacy and national security".

Biden's nominee as secretary of state Antony Blinken told his Senate confirmation hearing on Tuesday that the new administration will "review the entire approach and policy toward North Korea because this is a hard problem that has plagued administration after administration, and it's a problem that has not gotten better. In fact, it's gotten worse".