Defence Minister Kevin Andrews has declined to name the head of Islamic State [IS] during an interview with the ABC, citing "operational matters".

The US has placed a $10 million bounty on the head of Abu Bakr al-Baghdadi, also known as Abu Du'a, calling him "the senior leader" of IS and a "specially designated global terrorist".

During an interview with 7.30's Leigh Sales which coincided with the announcement that Australia was sending another 330 troops to help Iraqi forces battling IS, Mr Andrews was asked if he could name the terrorist group's leader.

"At the start of the war on terror back after 9/11, the military campaign was heavily focused on the leadership of Al Qaeda and it remained so for a long time. When it comes to IS who is the top leader and what sort of focus is there on his capture?" Sales asked.

Kevin Andrews: "Well, there's a cadre of leaders in the ISIL [IS] forces and we're not just dealing with one organisation. There's fluidity between organisations and individuals who are involved." Leigh Sales: "But there is a leader and a cabinet of IS, they run like a government." KA: "And that makes it more difficult in terms of the overall objective we're seeking to achieve here. But we will continue along the lines that we are." LS: "So just to be clear, who is the leader and what is the focus on his capture?" KA: "I'm not going to go into operational matters obviously." LS: "Can you name the leader of IS?" KA: "I'm not going to go into operational matters." LS: "I don't think it's operational, I think it's a matter of public record." KA: "I'm trying to answer your question as best as I can and that is ultimately our aim here is to degrade and to defeat ISIL. ISIL operates not just in Iraq but across Syria as well and there is fluidity between groups. There's not just one group involved and not one just group of individuals involved and so we have to counter that as best we can over the coming weeks and months." LS: "Minister, you're responsible for putting Australian men and women in harm's way in the cause of this mission, I'm surprised that you can't tell me the name of Islamic State's leader. The US State Department has a $10 million bounty on his head." KA: "As I said, ISIL is a combination of groups, Leigh, there is not just one individual involved in this. There are Australians involved in the senior leadership of ISIL or Daesh, and there is a fluidity between groups that we've seen over the past few months in that area. It's not just one person involved, there's a series of people involved and we must ultimately destroy all of them if we're going to degrade their operations in that area." LS: "The specific person who I have been referring is Abu Bakr al-Baghdadi."

Mr Andrews later tweeted that: "Focusing on individuals ignores the threat that extremist organisations present. We remain firm in our resolve to defeat Dae'sh."

Abu Bakr al-Baghdadi is believed to be the leader of Islamic State. ( Photo: AFP/HO/al-Furqan Media )

Earlier on Tuesday, Prime Minister Tony Abbott said 330 Australian troops would leave for Iraq on Wednesday, as part of a deployment which was first flagged six weeks ago.

Mr Abbott said the troops would be embarking on a two-year mission, with most put to work training Iraqi soldiers.

Australia joined the international effort to defeat IS militants in September, with a contribution of six F/A18 fighter jets, a surveillance aircraft, a refueller, 200 special forces soldiers, and 400 military support staff to the US-led mission.

Mr Abbott said while the international military coalition had been effective, "large swathes" of Iraq still remain under IS control.

"Our build partner capacity mission is all about trying to ensure that the legitimate government of Iraq has a trained and disciplined and capable force that understands the rules of armed conflict at its disposal to retake ... the territory which is currently under the control of the death cult [Islamic State]," he said.

Mr Abbott said the deployment would be reviewed in 12 months.

When the increased troop deployment was foreshadowed in March, Mr Abbott rejected criticism it represented "mission creep", saying instead it was the "successful execution of the original mission".