But so far Annan has been forced to confront a series of immediate problems that have damaged the UN's credibility.
The resignation of UN High Commissioner for Refugees Ruud Lubbers on 20 February should end controversy over a year-old case in which Annan had faced steady criticism.
But the UN Secretariat, including Annan himself, face further investigations into the Iraqi oil-for-food program, which have cited misconduct on the part of the program's director. There are probes into sexual abuse of women and girls by UN peacekeepers in Congo. The department of internal oversight is also under scrutiny.
Six U.S. Congressional committees originally focused on the oil-for-food inquiries are now pointing to the other revelations as proof of deep problems in the organization.
Annan has vowed to improve transparency and accountability. In his first major personnel move this year, Annan hired the head of the UN Development Program, Mark Malloch Brown, to be his chief aide.
UN spokesman Fred Eckhard said one of Brown's initial roles has been public relations.
"[Annan's] choice of Mark Malloch Brown, I think, reflected his sense that the UN needed to get up front and more aggressive in defending itself against an increasingly hostile segment of the media and the political spectrum," Eckhard said.
Annan could advance reform efforts through other key posts due to be filled in the coming months, including the heads of management, political affairs, and internal investigations.
He faces a deeply skeptical U.S. Congress, where some influential Republicans have called for his resignation. They have also introduced legislation on withholding U.S. funding unless the oil-for-food matter is properly handled.
There is still a sense that the UN would not be embarking on any reforms without the media and U.S. pressure, said Brett Schaefer, a research fellow at the Heritage Foundation, a private policy-research institute in Washington.
"The United Nations is a beast that is very reluctant to change and I think it's going to take a strong effort on the part of member states and the press to bring more transparency and accountability," Schaefer said.
Annan admitted yesterday that "ethical lapses and lax management" have been uncovered in the various inquiries. In an article in "The Wall Street Journal," Annan stressed his determination to carry through management reforms.
He also cited UN successes such as its response to the Southeast Asian tsunamis and its help organizing the Iraqi elections. He has offered UN help in drafting Iraq's constitution.
A top adviser to Annan, former U.S. diplomat Robert Orr, said it is important not to lose sight of the role the UN is already playing in areas of vital U.S. interest.
He noted President George W. Bush's emphasis in his State of the Union speech on recent elections in Afghanistan, Iraq, and the Palestinian territories. The UN was crucial to all three polls, Orr told a recent panel on UN reform in New York.
"It's very important to acknowledge this," Orr said. "The UN played a different role in each of these elections but the key role in making these things happen. The people in each government in each country were the source of the success of those elections. None of the three would have happened without the UN."
Annan plans to speak in March about his chief recommendations for UN institutional reform, including a possible expansion of the UN Security Council. A summit in September will address those issues.
Meanwhile, the U.S. Congress has commissioned a report for release in June -- the 60th anniversary of the UN's founding -- studying how the UN is serving U.S. interests.