Andrew Wilkie -- who resigned from Australia's top intelligence assessment agency, the ONA, last March to protest the government's stance -- said Howard's office deliberately skewed the truth and misled the public over Iraq's weapons capabilities.

"It was sexed up," Wilkie told the inquiry into the accuracy of intelligence reports in the lead up to the war. "Sometimes the exaggeration was so great, it was clear dishonesty."

Wilkie's claims echo the allegations that led to British arms expert David Kelly's suicide last month and is still causing shockwaves in British politics.

Wilkie claimed Howard's office removed ambiguous terms from ONA intelligence assessments and presented speculation as fact.

He believed intelligence agencies "did a good job" producing intelligence assessments but they were altered by Howard's office.

"The material was going straight from ONA to the prime minister's office and the exaggeration was occurring in there, or the dishonesty was occurring somewhere in there," he said.

Howard, who like his British and US counterparts has been accused of waging the war under false pretences, denied intelligence had been doctored.

"We didn't ask that the intelligence be distorted, I and my colleagues made a bona fide judgement based on the assessments that existed at the time," he told commercial radio.

The inquiry also heard evidence from former chief UN arms inspector in Iraq Richard Butler, who said he was "shaken" by the failure to find weapons of mass destruction (WMDs) in Iraq.

Butler remained confident WMDs would be located, saying he was certain they existed in Iraq when he was executive chairman of the UN Special Commission from 1997 to 1999, even though they were not discovered.

He told the inquiry, which is examining whether bogus intelligence was used to justify Australia's participation in the war on Iraq, that he could not understand why the WMDs remained elusive.

"I'm a bit shaken, as everyone is, by the fact that the country, now under occupation, hasn't yielded this treasure trove of WMDs," he said.

"I would remain confident though that if we can get hold of the people involved ... the authentic record will reveal a few caches of weapons here or there.

"Whether it will reveal the substantial quantity that's being talked of I don't know."

Butler said the United States could probably end the controversy over WMDs swiftly by revealing what former Iraqi deputy prime minister Tariq Aziz and other former high-ranking officals had told them under interrogation.

"Why aren't they putting us out of our misery by telling us the truth of these matters?" Butler asked, adding that he found the silence "puzzling".

"What arrangement has been made with Tariq Aziz? He knew everything," he said.

Butler said he was not in a position to assess whether the intelligence used to justify the war was accurate.

"The only honest answer I can give is I don't know, because I didn't see those intelligence reports," he said.

WAR.WIRE