Defence says Australian combat aircraft, special forces and training teams are making a vital contribution to the Iraqi army battle to retake Ramadi.
Australian combat aircraft, special forces and training troops have contributed to operations which have killed about 1000 Islamic State insurgents in bitter fighting around the Iraqi city of Ramadi.
Chief of defence force joint operations Vice Admiral David Johnston says IS is under growing pressure on multiple fronts and its ability to move forces and resupply was increasingly constrained.
Much of the fighting now centres on Ramadi, 100 kilometres west of Baghdad, which was seized by IS in May.
Some 500 of their fighters are believed to remain.
"An accurate number of how many have died in the fight is almost impossible to obtain," Vice Admiral Johnston told reporters in Canberra on Friday.
"We'd think more than 1000 Daesh (IS) fighters would have died."
Australia's 80 special forces facilitated air strikes for the Iraqi Counter-Terrorism Service brigade, the lead unit of Iraqi military forces seeking to expel IS forces from Ramadi.
That led to more than 917 air strikes.
The majority of those missions occurred in the vicinity of Ramadi, killing many IS fighters, the destruction of more than 420 defensive fighting positions and 85 IS vehicles destroyed, many of them vehicle-born improvised explosive devices.
The 300 Australians and 100 New Zealanders had now jointly trained more than 3000 Iraqi troops, many engaged in fighting around Ramadi.
"Iraqi commandeers have observed a commensurate improvement in the confidence of their forces who have received this training," Vice Admiral Johnston said.
There had been improvements in targeting, which combined with the Iraqi military shift to offensive operations had boosted the tempo of air strikes, including by Australian aircraft.
Since starting operations in October 2014, RAAF aircraft have flown more than 1000 missions, releasing more than 600 bombs.
That includes 12 missions over Syria during which nine bombs were dropped.
Colonel Matt Galton, who commanded the first training team rotation, said Iraqi troops had it in them to win the fight and that training had had a visible impact.
"It's a matter of time until they do retake Ramadi and hopefully, in the not too distant future, they will start to move further north," he said.