The UN Secretary General Kofi Annan has appointed a new chief of staff.
Mr Mark Malloch Brown is from Great Britain and is currently the head of the UN Development Program.
He replaces Iqbal Riza, of Pakistan, who announced his retirement two weeks ago.
The appointment is the start of a reshuffle which will give Mr Annan an opportunity in his last two years in office to put in place UN reforms and tackle the damage caused to the world body over corruption in the Iraqi oil-for-food program.
Mr Annan said Mr Malloch Brown would be valuable at the centre of UN work as well as "revitalize the UN system and ensure it is better equipped to deal with the scale and complexity of 21st century challenges."
Mr Malloch Brown will remain head of UNDP as well as chief of staff while the tsunami emergency continues in Asia and until a replacement is found. He left with Mr Annan on Monday for Jakarta, Indonesia, and a Thursday meeting with Asian leaders and an aid appeal.