Among the Iraq government's listed failures were reducing sectarian violence and passing laws on oil revenue sharing.
"While the Baghdad security plan was intended to reduce sectarian violence, it is unclear whether violence has been reduced," according to prepared testimony by David Walker, the agency's head.
"Average daily attacks against civilians have remained unchanged from February to July 2007," Walker said, despite Bush's addition of 30,000 US troops to Iraq this year.
Iraq's government had not met a number of political goals either.
The GAO report said: "Of particular concern is the lack of progress on de-Baathification legislation that could promote greater Sunni participation in the national government and comprehensive hydrocarbon legislation that would distribute Iraq's vast oil wealth."
Bush, on an unannounced visit to Iraq on Monday, pointed to what he called recent security successes in Anbar province and raised the prospect of fewer US forces if gains continued. But he said withdrawals could only happen from a position of strength.
"Had the US foreign policy makers read history, they would not get involved in any war after Vietnam"
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Many defence experts say the additional US troops will have to begin leaving Iraq by spring anyway unless the Bush administration extends their tours of duty over 15 months.
The GAO document was one of three reports ordered by congress that will be examined by legislators this month as they resume debate on the unpopular war.
Retired Marine General James Jones, head of an independent commission set up by congress, will report on Iraq security forces later this week.
The White House will submit its own assessment by September 15, after testimony to congress next week by David Petraeus, the US Iraq commander, and Ryan Crocker, US ambassador to Iraq.
Harry Reid, senate majority leader and a Nevada Democrat who wants US troops pulled out of Iraq, said the report showed Bush's strategy had failed to achieve results.
He said: "According to the president, when he set forth his escalation policy the purpose of the troop increase was to give the Iraqis space and safety ... to build a sustainable government to provide for their own security. None of this has happened."