The United Nations is just as necessary today as when it was started 60 years ago but it must be willing to change to ensure that it maintains its effectiveness, one of the candidates for its next secretary-general said Thursday.

Shashi Tharoor, U.N. undersecretary-general for public affairs, acknowledged that the United Nations had sometimes acted unwisely or failed to act but pointed out the body's many successes and noted that it had made "a huge difference" in the world.

"In 2006, I would argue that the need for ... a United Nations is stronger than ever," he said, highlighting its role in responding to cross-border problems such as terrorism, disease, drug trafficking and refugee movements, as well as promoting human rights and development.

"It is the resolution of these problems that remains at the very core of the United Nation's activities," the Indian U.N. candidate told an audience of about 300 people at a lecture sponsored by the Institute of Southeast Asian Studies.

But he said the need for U.N. reform has become clear as global threats and circumstances change, and he commended Secretary-General Kofi Annan for actively promoting change, notably in seeking greater efficiency and accountability.

Earlier this month, the General Assembly unanimously approved a series of management reforms that had been agreed upon at a summit of world leaders last September. But members put off many of Annan's most important management reform proposals until the next session of the General Assembly, which begins in September. Many of the proposals are meant to give the U.N. chief greater flexibility in running the world body.

"A vital task for the next secretary-general will be to ensure that the institution is ready for the challenges of the 21st century; moving on the changes that Secretary-General Annan has already introduced but prepared to deal with the unpredictable challenges of tomorrow," Tharoor said.

He said he was well-suited to take on the difficult task of leading the United Nations because of his 28 years of service in the organization.

"I have seen from the inside and the ground up most of the major challenges that a secretary-general can expect to face," Tharoor said. "It is of course a task I would welcome."

"Should our member states see fit to appoint me, I would seek both continuity and change. Continuity of the best traditions of the United Nations, and change because change is one of those best traditions.

He said education for girls would be a key goal if he were to get the top job.

"As the saying goes, when you educate a boy, you educate a person. But when you educate a girl, you educate a whole family," said Tharoor. "They will learn about sanitation, diseases and they will learn how to protect themselves against HIV/AIDS infection. Then they will bring up their children and pass on this knowledge."

Tharoor is one of two candidates who have formally been nominated by their countries to take on the top U.N. job after Secretary-General Kofi Annan's term expires at the end of the year.

In an informal, secret poll at the United Nations on Monday, Tharoor and the South Korean candidate, Foreign Minister Ban Ki-moon, were encouraged by the 15 Security Council nations to stay in the race. Candidates can come forward until the last minute, and the final vote is not expected until the fall.

Most U.N. diplomats generally agree that the next secretary-general should come from Asia, part of a tradition to rotate the job between regions. The U.N. chief can serve two five-year terms.

Thursday's lecture was part of a series co-hosted by Singapore's Institute of Southeast Asian Studies. Although Tharoor was invited to speak before India nominated him as a candidate for the top U.N. post, the research institute has invited all of the candidates to come to the city-state and speak.