The dignitaries are expected to join other foreign visitors - including Vice President Mike Pence and Japan's Prime Minister, Shinzo Abe - at the opening ceremony of the Winter Olympics.
Pence also has promised the US will soon unveil "the toughest and most aggressive round of economic sanctions on North Korea ever".
The North Korean delegation's arrival came a day after Kim Jong Un presided over a massive military parade in Pyongyang that was highlighted by the country's developmental intercontinental ballistic missiles, which in three flight tests a year ago showed potential ability to reach deep into the USA mainland when perfected.
The possibility of such a meeting loomed larger this week when Pence was asked about meeting North Korean officials and replied, "I have not requested a meeting, but we'll see what happens".
Abe also said he would convey to Moon Tokyo's position on a 2015 bilateral agreement on "comfort women" - many Korean - who were forced to work in Japanese military brothels during WWII while urging "future-oriented" two-way ties.
Pence avoided public criticism of Moon, congratulating South Korea on hosting the Olympics and pledging continued support in addressing the North's nuclear threat. But privately, officials said, Pence expressed concern to Moon about his more conciliatory tone toward North Korea.
Moon has embraced the Games as an opportunity for a thaw in tensions, calling them "Olympic Games of peace".
Its Samjiyon Orchestra, expected to perform at the opening ceremony and again on February 11, is led by Hyon Song-wol, an N-pop star who is also the director of the regime's agitprop bureau.
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It is the third Winter Games being held in Asia after the 1972 Sapporo Winter Olympics and the 1998 Nagano Winter Olympics. Kim's sister, Kim Yo Jong, was at the opening ceremony with North Korea's nominal head of state, 90-year-old Kim Yong Nam .
Kim Yong Nam on Friday took a picture with Moon and his wife Kim Jung-sook before entering the reception room.
She is scheduled to meet with South Korean President Moon Jae-in on Saturday.
U.S. Vice President Mike Pence, left, shakes hands.
Pence is in Pyeongchang at the same time as a high-level North Korean delegation including leader Kim Jong Un's sister, Kim Yo Jong, and nominal head of state Kim Yong Nam.
Pence, who will lead the USA delegation to the opening ceremonies Friday evening, met Thursday with South Korean President Moon Jae-in to press for a more clear-eyed approach toward the nuclear-armed neighbor to the north. Moon has looked at the games as an opportunity to pursue a diplomatic opening with North Korea - a move the vice president cautioned against. "I like the reconciliatory mood and I have high expectations", said Kim Sang-yoon, a 44-year-old businessman who drove almost five hours to see the opening ceremony with his wife and two sons.
The last time a South Korean president invited North Korean officials to the presidential Blue House was in November 2007, when late liberal President Roh Moo-hyun, the political mentor of Moon, hosted then-North Korean premier Kim Yong Il for a luncheon following a meeting between the countries' senior officials.
Analysts say the North's decision Kim Yo Jong to the Olympics shows an ambition to break out from diplomatic isolation and pressure by improving relations with the South, which it could use as a bridge for approaching the United States.