UN Secretary-General Ban Ki-moon started his new job with a clean slate, but his 'to-do' list is already daunting. The problem is not that there has been a sudden explosion of outbreaks of war, disease, weapons proliferation and suchlike since he took over from Kofi Annan. Rather, it is the unfinished business that his predecessor left behind. Among the most pressing tasks are stopping the genocide in Sudan's Darfur region, preventing Iran from developing nuclear weapons and making sure the UN's Millennium Development Goals to fight poverty stay on track. Then there are the negotiations to fight global warming that must be moved forward, and keeping the UN's operations free of the corruption and sex scandals that so badly tainted Mr Annan's second term. At some point in the near future, the organisation will also have to get more involved in Iraq and, depending on developments, the Middle East in general. Mr Ban is a renowned workaholic. In his previous incarnation as South Korea's foreign minister, he achieved what many in the country thought impossible - reforming the Foreign Ministry. By using the same formula, optimists might say, clearing the in-trays at the UN should therefore be a similar job, if on a bigger scale, for Mr Ban. The realists see it differently. Mr Annan's inability to get matters cleared up was not for want of trying. That so many important issues were left undone was not the fault of Mr Annan or his staff, but of the UN system itself. The organisation was founded by the victors of the second world war, half a century ago. It still functions as if nothing has changed since then in the geopolitical world. That, coupled with the archaic power of the veto held by the five permanent members of the Security Council - Britain, China, France, the Soviet Union (the predecessor of Russia) and the US - means that when it comes to matters of security, little is ever achieved. The most poignant example is Darfur, which Mr Annan made a desperate bid to resolve in his final days at the helm. After the Rwanda genocide in 1994, the world vowed that there could never be another such tragedy. Yet that is what is enveloping Darfur. On Tuesday, his first day in the new job, Mr Ban said Darfur would be his first priority, yet he will face an old problem: China and Russia are more interested in Sudan's oil than its human rights record, blocking action by the rest of the world. Mr Annan made reforming the UN, particularly the Security Council, a priority in the latter half of his second five-year-term. The idea of changing the way the organisation functioned was generally embraced. But disagreement reigned as to which countries should be given more prominence, and to what degree they should share the powers of the council's five permanent members. Expanding the council with nations that have grown in prominence over the past 50 years - notably Japan, Germany, India and Brazil - is important for the sake of international consensus. Rethinking the veto mechanism and finding a more efficient way of decision-making is as significant. Creating a leaner, better-functioning UN is essential. Mr Ban is in a good position to achieve such aims. As a career diplomat, he is highly versed in the ways of building bridges. Being Asian, he knows that the sometimes abrasive language of Mr Annan will not do. More fortunately, he has just embarked on his term and is not under pressure to establish a legacy as proof of his service. Instead, he has the chance to start afresh, without prejudices. And what better way to do this than to use his first year to focus on what Mr Annan was desperately trying to do as he was about to leave office: reform the UN. That does not mean that Darfur, nuclear proliferation, global warming and the rest should be ignored. Efforts must still be made to make the world safer and ensure that human rights are protected. Such issues cannot be dealt with effectively, though, without fixing the fundamental flaws in the system. Peter Kammerer is the Post's foreign editor.