IOC chief Thomas Bach, visiting the mountain resort which will host the Games next February, said he had been assured of cross-party support for the event after the impeachment of president Park Geun-Hye in a corruption scandal.
North Korea's bellicose nuclear posturing and Chinese anger at the deployment of a US missile defence system in South Korea have added to an unsettled atmosphere in East Asia.
But Bach said he had no concerns about the 2018 Games after meeting the acting president and parliamentary speaker in Seoul on Tuesday.
"We could hear and feel the great support which is going across all political borders," the International Olympic Committee (IOC) president told reporters.
"Because the Koreans feel... that these Games are a good opportunity for Korea to unite again and be united also in support of their athletes," he added.
"Because now the country is going through a difficult period of many political divisions."
While Park was ousted over an influence-peddling scandal, nuclear-armed North Korea also launched four ballistic missiles this month in its latest provocative test.
Despite enduring tensions between the two Koreas, who remain technically at war, Bach expressed hopes that the North -- which boycotted the 1988 Seoul Olympics -- will take part.
The South's political leaders had agreed that the Olympics will be "open to everybody", he said, when asked about North Korea.
- 'Korea will deliver' -
"This is the mission of the Olympic Games, to welcome the world," said Bach. "The political tensions in the region will play no role in this.
"This is the philosophy of the Games. And also in this respect I've no doubt that Korea will deliver and will offer its great hospitality for everybody."
Separately, China has vowed to "resolutely take necessary measures" and Chinese protesters have targeted South Korean retailers after the deployment of the THAAD missile-defence system in South Korea.
South Korea's Yonhap news agency has reported that China has banned travel agencies from selling trips to South Korea in retaliation for THAAD.
But Lee Hee-Beom, the Games' chief organiser, stressed Pyeongchang had a "very close working relationship" with Beijing -- which will host the next Winter Olympics in 2022 -- and said he expected a lot of Chinese fans to come.
"We expect that a lot of Chinese travellers and Chinese spectators will come to Pyeongchang and enjoy the Games," said Lee.
Bach and Lee were speaking as the IOC's coordination commission wrapped up its penultimate pre-Games assessment of preparations for in Pyeongchang.
Commission chief Gunilla Lindberg said she was "optimistic" about Pyeongchang, where building work is on track and 17 test events have been held since December.
But she said there are a few concerns over transport and accommodation in the remote region -- and particularly, about creating excitement and engagement among fans.
"I think the crucial thing now is for POCOG (organising committee) with help maybe from some Korean companies to reach out, also for the Korean people to feel proud of their country," Lindberg said.
Lee added that the Games were looking at a 300 billion won ($262 million) deficit, which may be plugged by encouraging "public institutions" to weigh in with support.
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