Ashraf Jehangir Qazi, a veteran diplomat who has had "a distinguished career" and served in key posts around the world, was chosen from a short list of three "highly qualified" candidates after extensive consultations, UN associate spokeswoman Marie Okabe said.
The other contenders were former Indian Foreign Secretary Salman Haidar and former Thai Foreign Minister Surin Pitsuwan, she said. Like Qazi, they are Muslims.
Annan has had difficulty finding a qualified candidate to go to Baghdad to take on the top UN job. He said several candidates initially said "yes" but then called a week later telling him they had to say "no" because their families objected.
He had promised a decision by 2 July, but the announcement was delayed because Annan, who has been travelling in Africa and Asia, needed to get approval from Pakistani President General Pervez Musharraf, a well-informed UN official said on condition of anonymity.
Qazi served as Pakistan's high commissioner to India as well as ambassador to China, Russia, the former East Germany and Syria. He has held diplomatic assignments in Copenhagen, Tokyo, Cairo, Tripoli and London.
Annan had some difficulty
finding a qualified candidate
He has a master's degree in economics.
The new UN special representative to Iraq will replace top UN envoy Sergio Vieira de Mello, who was one of 22 people killed in the 19 August 2003 bombing at UN headquarters in Baghdad.
Spate of attacks
The secretary general ordered all UN international staff to leave Iraq in October following a second bombing at UN headquarters and a wave of attacks targeting foreign workers.
Okabe said Qazi must first be released from his current duties in Washington. He will then come to UN headquarters in New York in a week or two for briefings and consultations before being deployed to Baghdad at a later, as yet unconfirmed date.
The UN must get "the sufficient security guarantees from both the Iraqis and from the forces on the ground ... before he can be deployed," but Annan intends to have Qazi based in Baghdad, said a spokesperson.
The resolution adopted last month by the UN Security Council authorised the establishment of a new unit in Iraq charged with providing security for UN staff and facilities.
Georgia and Nepal have offered troops for this unit, according to diplomatic sources speaking on condition of anonymity.