Neither Labor nor the Coalition - both of which backed the 2003 invasion - has supported an inquiry beyond two inquiries into the intelligence supplied to former Liberal Prime Minister John Howard ahead of his decision to go to war.
Howard, while conceding that "mistakes were made", has consistently denied misleading Australians over Saddam's non-existent weapons of mass destruction used as justification for the invasion.
He will again make his case to the Lowy Institute in Sydney on April 9, the anniversary of the fall of Baghdad.
But Rod Barton, a former United Nations weapons inspector and former director at the Defence Intelligence Organisation, does not understand Howard's contention that he had been given "a very strong intelligence assessment" that Iraq had a WMD stockpile.
"I'm not going to call him a liar but I don't know why he said that," he told ABC radio. "It was quite clear from the inquiries, in fact, that the intelligence wasn't very good regarding WMD and it's a puzzle why Mr Howard continued on with that line."
Independent MP Andrew Wilkie, at the time of the invasion working with the Office of National Assessments, says the war was "unethical, unnecessary and illegal", and is a strong advocate of an inquiry.
The ONA is the key intelligence adviser for Australian prime ministers.
Wilkie left the ONA in protest as, despite the lack of definitive intelligence, Howard prepared to send special forces, warships and jet fighters to Iraq.
General Peter Cosgrove, at the time Chief of the Defence Force, does not believe Howard lied about WMDs, but admits to "mixed feelings" about the war and concedes mistakes were made, especially after Saddam fell.
He told the ABC he was uncertain if the war had made the world safer.
"There was never going to be a sort of a line drawn under global terrorism as a result of Iraq," Cosgrove said.
Many critics believe Australia's profile as a potential terrorist target was in fact increased by its solid support for the invasion.
Critics demanding an inquiry also fear that without an inquiry to determine the real reasons and process behind Howard's decision to go to war, Australia could be trapped into further conflicts.