Aust-trained Iraqi troops performing well

Iraqi troops trained by Australians and New Zealanders are performing well on the front line against Islamic State.

Defence force chief Mark Binskin says Australian special forces had so far qualified more than 800 counter-terrorism service personnel in advanced skills while the team working with NZ had trained more than 2100 regular Iraqi soldiers.

"Their performance on operations ... is above that of the other Iraqi security forces that haven't been through it," the air chief marshal told a Senate estimates hearing on Wednesday.

The three to five year mission aimed to train Iraqi security forces to a stage where they could retake control of their country.

Daesh (also known as IS) had a say in that, but the question was how long could its followers withstand getting bombed every time they stuck their head up, Air Chief Marshal Binskin said.

"We are seeing indications that Daesh's morale is taking a hit. We know their leadership morale is down because they are being targeted."