The man tipped as a possible leader of post-Saddam Iraq has warned there would be "no room" for the United States in am interim authority.
Mr Ahmed Chalabi, leader of the Iraqi National Congress, said he hoped there would be full elections held in Iraq within two years.
Until then the interim authority must be formed by the Iraqi people, he said.
"We hope elections would be held within two years in Iraq after a constitution is drafted by Iraqis, approved by a constituent assembly and put to a free public referendum," Mr Chalabi told the BBC.
Asked whether that meant Iraq would have a US administration until that vote, he said: "We see no room for US administration and indeed the United States has said they hope to assist Iraqis in forming an interim Iraqi authority."
Mr Jay Garner, the retired US general appointed director of the Pentagon's new Office of Reconstruction and Humanitarian Assistance, will oversee civilian affairs in Iraq in the immediate aftermath of war.
A conference bringing together representatives of Iraq's diverse groupings to help form an interim authority is set to take place soon.
British Foreign Secretary Mr Jack Straw earlier assured MPs that it was Britain's "guiding principle" that Iraq should be governed by the Iraqis themselves "as soon as possible".
"We therefore support the early formation of an Iraqi Interim Authority, which progressively will assume the functions of government. The coalition will need to work with the UN in establishing this body," Mr Straw said in a statement to the Commons.
"I envisage at the right moment, a national conference bringing together credible representatives from all parts of Iraqi society to agree on the establishment of the Interim Authority."
PA