Officials in Iraq and the Emirates, however, denied that Barzan al-Tikriti had defected. Attempts to reach al-Tikriti in the Emirates on Wednesday were unsuccessful.
Salah al-Shaikhly, spokesman for the opposition Iraqi National Accord, said al-Tikriti has been in the United Arab Emirates for over a week.
"We understand that the Emirates has granted him permission to stay there on the condition he not pursue any political activities," al-Shaikhly said from London.
In Abu Dhabi, an official denied that al-Tikriti was in the Emirates.
"Barzan al-Tikriti is not in the Emirates and he did not submit a request to live in the Emirates," the official said, speaking on condition of anonymity.
The head of the official Iraqi News Agency, Odai al-Ta'i, said reports of defection are "totally bare of truth." He said al-Tikriti was visiting family in Switzerland but would not say how he could be contacted.
A statement from the Iraqi National Accord, received in Cairo, said al-Tikriti feared his life was in danger in Iraq.
Al-Tikriti served as Iraq's ambassador to the United Nations in Switzerland for a decade and was recalled last summer. He went back to Baghdad in December, denying rumors that he had delayed his return because he was seeking to defect amid disputes with Saddam.
His wife was undergoing treatment for breast cancer in Switzerland and died in November.
In March, Iraqi security forces interrogated al-Tikriti after one of his assistants fled the country and joined an opposition group.
Saddam has at least two other half brothers.