Prime Minister Rudd criticized the US justification for the 2003 invasion of Iraq as 550 Australian troops packed up to leave.
Labor leader Kevin Rudd made the remarks a day after ordering his country's 550 combat troops to head home after five years in Iraq.
As one of the United States' staunchest allies, Australia was quick to pledge military support for the US-led coalition invasion of Iraq in 2003. But that decision was made by conservative prime minister John Howard, whose 11 years in office came to an end in November's election.
Bringing home Australia's small but politically significant contingent of combat troops was one of Mr. Rudd's main election campaign pledges.
He dismissed one by one the reasons used by the Howard administration – and by association the Bush administration – to topple Saddam Hussein.
"Have further terrorist attacks been prevented? No, they have not been, as the victims of the Madrid train bombing will attest," Rudd told Parliament.
"Has any evidence of a link between weapons of mass destruction and the former Iraqi regime and terrorists been found? No.
"Have the actions of rogue states like Iran been moderated? No ... Iran's nuclear ambitions remain a fundamental challenge.
"After five years, has the humanitarian crisis in Iraq been removed? No, it has not."
Rudd said there had been a "failure to disclose to the Australian people the qualified nature of the intelligence. For example, the prewar warning that an attack on Iraq would increase the terrorist threat, not decrease it."