"Yes, they [Iraqi security forces] captured someone that might be him. They are waiting for the DNA tests so nothing is for sure yet," Allawi's spokesman Taha Husain said.
Confusion has shrouded the whereabouts of al-Duri since a senior Iraqi national guard commander denied reports by his subordinates and the interior ministry that he was now behind bars.
Iraqi police earlier said al-Duri was captured while he was receiving medical treatment on the road between Tikrit and Kirkuk.
The man who was Saddam's number two in Iraq's Revolutionary Command Council is suffering from leukaemia and his health has deteriorated, Iraqi officials said.
Officials of the interim government earlier said there was a "75-90% chance" that the captured man was al-Duri - one of the most wanted men in Iraq.
Local journalist Muhammad al-Badri told Aljazeera that he may have been captured but was unsure.
"We haven't got any information about the arrest of al-Duri. Raids and search campaigns began two days ago in Tikrit and districts nearby," he said.
"I think al-Duri was arrested during these raids but the arrest has not been announced," he added.
However, Iraq's Defence Minister Hazim al-Shalaan said reports on the capture were without foundation.
"We don't have any information regarding this issue. What
has been said of a statement by the Defence Ministry is
baseless," he told Lebanon's LBC television channel.
Occupation authorities had accused him of coordinating attacks against US forces in the country.
But observers have questioned claims that al-Duri had connections with the Iraqi movement to oppose the presence of US-led troops.
"It is the people's resistance and I do not think the arrest will affect the resistance"
Abd al-Amir Alwan,
Dr Nabil Muhammad Salim from the centre of international studies in Baghdad University doubted that he was linked to the ongoing opposition to US-led forces.
"Many Iraqis do not think he had a link with the Iraqi resistance whose circles were very far from the key members of the former Iraqi regime," he said.
London-based political activist Abd al-Amir Alwan told Aljazeera his arrest would be used for political gain by the interim Iraqi government.
"The US administration and the Iraqi government want to enlarge this in order to divert the attention from the issue of the legitimacy of the Iraqi government and the resistance," he said.
"Accusations that Saddam Hussein, Izzat al-Duri or Abu Musab al-Zarqawi were behind the resistance were false as there is a vast resistance in the north and the south of Iraq and it is not related to Izzat al-Duri or any other person. There are many factions refusing the occupation," he said.
"The man is part of the former regime and he is ill and I think that he was just a follower to Saddam. What made him important was his close relationship with Saddam. Giving the incident such significance is camouflage and misleading.
"It is the people's resistance and I do not think the arrest will
affect the resistance," he added.
'Not a surprise'
However, Paris-based Iraqi journalist Samir Ubayd told Aljazeera: "The arrest of Izzat al-Duri will definitely make Iraqi people happy and sadden former Baath cells to which he belonged. The arrest was not a surprise.
"The arrest does not mean anything particularly after the toppling of the former regime in which Izzat was just a tool in the hand of Saddam. So I think there was not a vast resistance he was leading.
"The resistance has been popular and now it has got rid of accusations of working with al-Duri," he added.