A campaign calling for an inquiry into why Australia went to war in Iraq is gaining momentum.

The so-called Iraq War Inquiry Group is now an incorporated body, which will allow it to start appealing for donations and register federally with the Australian Securities and Investments Commission (ASIC).

The group, which includes former generals, diplomats, academics and senior public servants, says Victoria's company registration laws were the most accommodating for the group's registration.

According to its website, the new organisation includes members such as former Defence Intelligence Organisation (DIO) technology director Rod Barton, former ADF chief general Peter Gration, and former chief of Army and West Australian governor John Sanderson.

Another member, former defence department secretary Paul Barratt, says the aim of the inquiry group is not to conduct a witch hunt.

"We've explicitly disavowed any intent to be out on a punitive expedition to try to get people for whatever they may have done in 2002 and 2003," he told the ABC.

"It's always healthy to have a clear view of the past to know what actually happened so that we can learn from it for the future.

"This is not about satisfying historical curiosity, it's about looking at the past.

"We know there were some mistakes made, we know there were some things that were not particularly admirable done, but we want to learn from all that and say what's a better way to make decisions like this in the future.

"And this is not just an abstract theoretical question, there are constant drumbeats of 'let's attack Iran', well where will Australia sit in relation to that and how will we make that decision?

"Will we make that decision in a robust and effective way or will we make it in the amateurish way in which we made it in relation to Iraq?"

'Dodgy intelligence'

Mr Barratt says it is already well established that Australia committed to the Iraq conflict on the basis of what he calls "dubious" evidence.

"They did rely on foreign intelligence which was quite clearly cooked up to sell the war to the British and American public," he said.

"Our own Defence Intelligence Organisation was advising the government then that that was very dubious.

"When we were told that Saddam Hussein had tried to buy uranium from Iraq, DIO... were saying, 'no, there is no evidence of a nuclear weapons program, there's no evidence of any new effort'.

"So a very important question for government is what efforts did you make to satisfy yourself that the advice from the allies was to be preferred over the advice from the people you pay to make these assessments?

"We never ask ourselves the question: are these people trying to sell us something?"

The former lieutenant general who led Australian forces in Iraq, Professor Peter Leahy, says he thinks such an inquiry could be a good idea.

"If there is enough public support for it, I think it's worth considering," he said.

"I'm comfortable. I think the right decisions were made, and the right decisions and actions were taken, but if there are people who are uncomfortable - well let's answer their questions.

"I think it's a good thing to look at what we do as a nation - to look at our motives; to look at how we've performed.

"So I don't feel at all challenged by the fact there may be a broader discussion or an inquiry that should be looking at the Iraq war."

But Mr Leahy said one of the most important things for such an inquiry to look into would be what he sees as the need for more parliamentary oversight of the decision to go to war.

"I think there should also be more public debate and discussion about decisions to go to war, but also the decisions to stay at war," he said.