The new Secretary-General of the United Nations received an early reminder of the pitfalls of international diplomacy when he failed to restate the UN's opposition to the death penalty during remarks about the execution of Saddam Hussein.

Ban Ki Moon, the former South Korean Foreign Minister, received a warm welcome from staff at the UN headquarters on Manhattan's East River when he turned up for his first day at work yesterday.

But his spokeswoman was forced to issue a clarification after Mr Ban said that capital punishment should be a decision for individual member states.

The UN has an official stance opposing capital punishment and Ban’s predecessor Kofi Annan reiterated it frequently. The organisation's top envoy in Iraq, Ashraf Qazi, restated it again after the former Iraqi dictator was hanged on Saturday.

Mr Ban, however, took a different approach, never mentioning the UN's ban on the death penalty in all its international tribunals, and the right to life enshrined in the Universal Declaration of Human Rights adopted by the General Assembly in 1948.

"Saddam Hussein was responsible for committing heinous crimes and unspeakable atrocities against Iraqi people and we should never forget victims of his crime," Mr Ban said in response to a question about Saddam’s execution. "The issue of capital punishment is for each and every member state to decide."

It was unclear whether Mr Ban was simply unaware of UN policy or did not agree with it, but his new spokeswoman, the Haitian journalist Michele Montas, insisted that there was no change despite what she called "his own nuance".

"The UN policy still remains that the organisation is not for capital punishment," she said. "However, the way the law is applied in different countries, he left it open to those different countries."

The death penalty is legal in Mr Ban’s homeland, as it is in many other countries including the United States, Russia, China and much of the Middle East.

Dozens of staffers applauded Mr Ban as he walked through a throng of cameramen and photographers and headed straight to the Meditation Room, where he bowed his head in tribute to UN peacekeepers and other employees who have died in service.

He surprised others by walking into the staff cafeteria for lunch, waiting in line with his tray to pay for a meal of meat with rice and a bottle of water.

Speaking to reporters, Mr Ban vowed to end mistrust of the United Nations and called for action to tackle "daunting" problems from crises in Darfur, Lebanon, Iran and Iraq to the goal of cutting extreme poverty by half by 2015.

He also renewed his promise to give priority to the North Korean nuclear issue and to defend human rights.

The South Korean announced that his first overseas trip will be to attend the African Union summit in Addis Ababa, Ethiopia, on January 29-30, and he hopes to meet Sudan’s President Omar al-Bashir there.

He said that he would meet his special envoy on Darfur, Jan Eliasson, today and put his "highest attention" on efforts to resolve that conflict. Tomorrow, he will chair a meeting of the Darfur Task Force, which includes all UN agencies involved in trying to end the conflict.

Mr Ban also addressed hundreds of UN staff members in New York and via teleconference at eight locations around the world, urging them to maintain the highest level of ethics and discipline in the face of recent criticism about lack of accountability, ethical lapses and inefficiency at the UN.

The new Secretary-General has said his first priority will be to restore trust in the United Nations, whose reputation has been battered by the oil-for-food scandal in Iraq, corruption in the UN's purchasing operations and sexual abuse by UN peacekeepers.

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