The next United Nations Secretary General, Ban Ki-moon, has promised to work to reform the world body and help resolve the stand-off over North Korea.
Mr Ban is expected to face tough challenges over North Korea
He said he would appoint a special envoy to try to end the crisis over the North's nuclear programme.
Mr Ban made his comments in a farewell speech to the South Korean parliament, as he formally stepped down from his post as the country's foreign minister.
He thanked South Koreans for supporting him in his campaign to become UN chief.
"This diplomatic triumph belongs to all South Koreans," Mr Ban is quoted as saying. "The honour can never be mine alone."
Mr Ban takes over as head of the UN on 1 January, succeeding Kofi Annan.
"After being appointed as secretary general, I was somewhat scared and humbled to think that all issues in the world, such as UN reform, regional conflict, terrorism, and proliferation, are related to myself," he told his parliamentary colleagues.
One of the issues he is keen to focus on is greater internal accountability and transparency.
"The reform of the UN, which has been put off for the past 60 years, must be carried out in earnest," he said.
He has also that he wanted to rebuild trust in the organisation.
But the impasse over North Korea's nuclear programmes will undoubtedly be another of his priorities.
"With regard to resolving the North Korea nuclear issue and maintaining peace on the Korean peninsula, I plan to best utilise my authority as secretary-general and contribute to resolving the issue peacefully as soon as possible," Mr Ban said.