The report by Philip Flood found Australia's Defence Intelligence Organisation and Office of National Assessments failed to judge accurately the extent and nature of Iraq's weapons of mass destruction (WMD) programmes.
"There has been a failure of intelligence on Iraq WMD. Intelligence was thin, ambiguous and incomplete," Flood said in the report, mirroring similar US and British inquiries.
But Flood's report also said that there was no evidence of political pressure "to bolster the case for war".
"The inquiry received no indication that any analyst or manager was the subject of either direct or implied pressure to come to a particular judgment on Iraq for policy reasons, or to bolster the case for war.
Flood also said: "It is significant that, using similar but not all the material available to the UK and the US, Australian assessments on Iraq's capabilities were on the whole more cautious, and seem closer to the facts as we know them so far."
"It is significant that, using similar but not all the material available to the UK and the US, Australian assessments on Iraq's capabilities were on the whole more cautious, and seem closer to the facts as we know them so far"
ex-Australian intelligence chief
The separate inquiries by the United States and Britain into their spy agencies revealed last week an over-reliance on patchy intelligence material, shortcomings in supervision and a failure to circulate key intelligence to those who needed to see it.
Australian Prime Minister John Howard, who is tipped to call an October election, welcomed Flood's finding that there had been no evidence of politicisation of Australia's intelligence.
"We did not heavy the intelligence agencies. I reject (claims) that we took the country to war based on a lie," Howard, a close ally of US President George Bush, told reporters in the northern city of Brisbane.
"If I had my time again I would take the same decision (on joining the Iraq war)," said Howard, who sent 2,000 troops to the US-led invasion of Iraq in 2003.
But the report into Australia's intelligence services also said they failed to gauge the threat from Asian groups like Jemaah Islamiya (JI).
Threat posed by Southeast Asian
groups was 'underestimated'
It found Australia's intelligence agencies, like their counterparts in Asia, had underestimated the extent of the threat posed by groups in Southeast Asia.
"Indeed it was fundamentally a regional intelligence failure," Flood said.
The report said Australian intelligence should have known more about the "terrorist capabilities and intentions" of JI prior to the October 2002 Bali nightclub bombings.
The al-Qaida-linked JI has been blamed for the Bali bombing, which killed 202 people, including 88 Australians.
But Flood said there was no indication any Australian agencies had specific intelligence warning of the Bali attack.
Howard said he would more than double the budget of the Office of National Assessments as recommended by Flood. Australia's version of the US National Security Agency will see its budget jump to A$25 million ($18 million).
Howard, whose eight-year-old government is seeking a fourth term in office, ordered the independent intelligence inquiry after a parliamentary report found the Iraqi threat of weapons
of mass destruction had been overstated by Australian spy agencies.
Australia's centre-left opposition Australian Labor Party, polling neck-and-neck with the government, has called for a top-level inquiry into the running of Australia's intelligence agencies.