It comes a day after President George W Bush declassified parts of the report.
Some opposition Democrats suggest that the president’s aides are keeping it in draft form so that it does not reach the US public.
"The American people deserve the full story, not those parts of it that the Bush administration selects," Democrat Senator Edward M Kennedy said.
White House Press secretary Tony Snow said releasing the full report would jeopardise the lives of agents who gathered the information.
"We don't want to put people's lives at risk," Mr Snow told a White House news briefing.
Election season stoush
The White House has also denied that it was holding back the intelligence assessment of Iraq until after November 7 elections in which the unpopular war is expected to be a factor.
"They're just flat wrong," Mr Snow said. "There is not a waiting Iraq document that reflects a national intelligence estimate that's sitting around gathering dust waiting till after the election."
The document has given both political parties new ammunition leading up to November's mid-term elections.
For Republicans, the report provides more evidence that Iraq is central to the war on terrorism and can't be abandoned without giving jihadists a crucial victory.
For Democrats, the report furthers their argument that the 2003 Iraq invasion has inflamed anti-US sentiments in the Muslim world and left the US less safe.
NIE assessment
Mr Snow said that US Director for National Intelligence John Negroponte had undertaken a National Intelligence Estimate on Iraq and that it was still underway.
It will be the consensus view of all 16 US spy agencies.
"They're just beginning to do their work on it," said the spokesman, who described the report as being "in the very early stages of composition. And that's what it is."
On Tuesday, Mr Bush's homeland security adviser Frances Townsend likewise denied political motives and said the report would be finished in January 2007.
According to the Council on Foreign Relations think tank, a typical NIE takes three to six months to complete but can be done on a "fast track" that requires just two to three weeks.
Newsweek magazine reported in September that the Pentagon's intelligence arm had warned lawmakers in secret briefings that Iraq "could dissolve into civil war if Iraqi security forces don't soon get their act together."