UN sources said Alicia Barcena of Mexico was expected to be named undersecretary-general for administration and management, a post previously held by the US, which now wants political affairs or peacekeeping.
Speaking to Al Jazeera in an interview, Ban said that his first two priorities would be to streamline the secretariat to ensure efficiency and to promote dialogue and negotiations with leaders in regional conflict areas such as the Middle East and Africa.
"We need to egange with leaders, in particular the Sudanese government, to deal with the Darfur crisis," he said.
Ban, 62, South Korea's former foreign minister, will be the first Asian secretary-general in 35 years.
Ban's big decisions are yet to come, including the naming of a deputy secretary-general and how to please Security Council powers insisting on top appointments.
Russia will remain in charge of UN European operations in Geneva and China is to get the undersecretary-general post for economic and social affairs, diplomats reported.
Asked about the credibility of the Security Council and the US power within it, Ban said that the US was without a doubt the most important power in the UN and therefore the "participation of the US is crucially important".
|"Reform of the Scecuirty Council is most important and is a most sensitive one. We need a consensus on a formula to facilitate such reform"|
Ban also said that he believed the US held the same principles as the UN to uphold human rights, freedom and liberty, common prosperity and security.
Ban said: "Reform of the Security Council is most important and is a most sensitive one. We need a consensus on a formula to facilitate such reform."
Asked about how the UN would be able to do their job while at the same time respecting the sovereignty of countries, Ban said: "The concept of responsibility to protect was an important acheivement at the UN world summit last year. But we need to solidify the framework of this concept."
On the issue of North Korea, Ban said that he hoped North Korea would respond sincerely to a peaceful resolution through six-party talks.
First posts appointed
Nambiar, a professor and former deputy national security adviser to the Indian government, is a former ambassador to the United Nations, Pakistan, China, Malaysia and Afghanistan.
Montas, a journalist, was the wife of murdered Haitian radio broadcaster Jean Dominique and featured in the 2004 Jonathan Demme documentary, The Agronomist. Montas kept alive the radio station they ran until threats against her life and her staff made it impossible.
She left for the US in 2003. She has had posts in the UN public information department for the past few years, including spokeswoman for the General Assembly in 2004.
With strong support from the US and China, Ban was chosen as secretary-general over six rivals by the 15-nation Security Council, a decision confirmed by the 192-nation General Assembly in October.
Annan, 68, who officially ended his 10 years in office at midnight on Sunday, intends to leave New York for Geneva on Monday and take a long rest with his Swedish wife, Nane, and then organise a foundation for African agriculture.