The Minister for Defence, Joel Fitzgibbon, said the military was overstretched with its commitments in East Timor, Afghanistan and Iraq. "Roughly half of our infantry and cavalry is somehow tied to those deployments," he said. "This is an unsustainable position." The Iraqis had not asked the Australian troops for help in 20 months, he said, and they were needed elsewhere.

The Howard government had cited several reasons for the war, including preventing more terrorist attacks, stopping Iraq giving weapons of mass destruction (WMD) to terrorists, preventing other rogue states giving WMD to terrorists, and ending the crisis in Iraq. "On every count, we on this side of the house rejected these arguments then as we continue to reject them now," Mr Rudd said. "Have further terrorist attacks been prevented? No they have not been. Has any evidence of a link between WMD and the former Iraqi regime and terrorists been found? No.

"Have the actions of rogue states like Iran been moderated? No. After five years, has the humanitarian crisis in Iraq been removed? No it has not." Mr Rudd's attack riled the former foreign affairs minister, Alexander Downer. "Can't you rise above this?" Mr Downer interjected from the back bench.

"You're supposed to be the Prime Minister of Australia, not the Labor spokesman." Brendan Nelson, the Opposition Leader and the last defence minister in the Howard government, maintained that al-Qaeda's attacks on the US on September 11, 2001, justified invading Iraq. The world could not afford the risk that Saddam Hussein had weapons of mass destruction, he said, and Iraq today was safer as a result. He reminded the House that Mr Rudd, as opposition foreign affairs spokesman, said in 2002 there was "a significant threat of weapon of mass destruction from Iraq".

Dr Nelson admitted errors had been made. In hindsight, the Iraqi army should not have been dismantled and the civil service should not have been purged of all members of the pro-Saddam Baath Party. Provision of basic services by Western contractors was also a mistake, he said. Dr Nelson accepted that the role of the combat troops in Iraq was over but said Mr Rudd should have replaced them with trainers to help the Iraqi forces.

Mr Rudd said the Government would soon release a national security statement so war could not be waged in such a manner again. "Our Government is committed to ensuring that our national security arrangements are focused, co-ordinated and effective, and that the actions of government are accountable," he said.