The DPRK top leader Kim Jong-un and US President Donald Trump are set to kick off two days of meetings in Hanoi on Wednesday, beginning with a dinner where they are expected to exchange pleasantries in a bid to warm up tough talks over denuclearization.

Both Kim and Trump arrived in Hanoi on Tuesday for their second summit.

While their historic first summit, in Singapore last June, focused on breaking the ice to pave the way for full-scale diplomacy for denuclearization of the Korean Peninsula, improved ties and a peace regime, they now face a more daunting task of yielding specific deals on details beyond a vaguely worded joint statement.

According to the White House, Kim and Trump plan to have a brief "one-on-one" meeting followed by a "social dinner". US Secretary of State Mike Pompeo and acting chief of staff Mick Mulvaney will dine with them. Two aides to Kim are his sister Kim Yo-jong and Vice-Chairman of the Workers' Party Kim Yong-chol.

The mood in the dinner session is likely to serve as a tone-setting test of this week's summit results that may decide the future of the peace process stalled after the Singapore meeting.

Full-fledged negotiations on what would be the agreement from the summit are expected on Thursday.

Some media reports from the Republic of Korea said the two sides will have another round of working-level talks on related issues ahead of the Kim-Trump meeting, but there was no official information about the talks.

Trump is scheduled to hold separate meetings with Vietnamese President Nguyen Phu Trong and then meet Prime Minister Nguyen Xuan Phuc from 11 am (local time).

Kim's pre-summit schedule remains unclear. He visited the Democratic People's Republic of Korea's embassy in Hanoi on Tuesday evening. He is likely to meet the Vietnamese leaders during his two-day "official goodwill" visit to the Southeast Asian nation after the summit as local media claimed Kim will leave the country on March 2.