She was also "too accommodating of the other personalities on the foreign policy team, like the vice president and the secretary of defence, and too deferential to those individuals."
Case for war
McClellan has written a book, set to be published next week, in which he accuses the Bush administration of manipulating the case for the war on Iraq.
"Contradictory intelligence was ignored, intelligence that had high level of confidence was combined with a package of intelligence that had a low level of confidence"
Excerpts of What Happened: Inside the Bush White House and Washington's Culture of Deception
were published in US newspapers on Wednesday.
Rice, on a visit to Sweden, denied that the US had misled the public about its reasons for the war, saying Bush was "very clear about the reasons for going to war," and linking it to Iraq's alleged flouting of UN disarmament resolutions.
And even if it turned out that Iraq did not have weapons of mass destruction, she said, the US was "not alone" in the world in its knowledge he had used them in the past and in its belief he still had them.
McClellan, however, reiterated his claim that the Bush White House was guilty of exaggerating the threat from Iraq.
"At the same time, as we accelerated the buildup to the war, the information we were talking about became a little more certain than it was. The caveats were dropped.
"Contradictory intelligence was ignored, intelligence that had high level of confidence was combined with a package of intelligence that had a low level of confidence.
"Together that made it sound like the threat was more urgent, more grave than it turned out to be," McClellan said.
The former Bush press secretary defended his position, saying he did not object to the selling of the war in Iraq at the time because he, like others in the US, gave the president the benefit of the doubt.
"My beliefs were different then. I believed the president when he talked about the grave and gathering danger from Iraq."
McClellan is believed to be one of the first of the president's Texas-based inner circle to publicly criticise his administration
He said he wrote the book in the hope of changing the "permanent campaign culture" of Washington - which he said he and Bush had hoped to change from the White House but instead "got caught up in".