Australia will send another 330 soldiers to Iraq on Wednesday in a training mission set to last two years.
Prime Minister Tony Abbott said the troops would be partnered with 100 New Zealand military personnel.
The mission's purpose is to help train the Iraqi army so that it can gain and hold ground against Islamic State (IS) militants, he said.
The mission, to be based about 30 miles north of the capital Baghdad, is expected to be operational by May.
The deployment was first announced in March.
"We won't have a combat role. It is a training mission not a combat mission," Mr Abbott told journalists at a press conference in Canberra on Tuesday. "I can't tell you that this is risk free."
"The work of the coalition against the Islamist death cult has been effective," he went on, referring to IS.
"We have seen the Iraqis retake [the city of] Tikrit... we have seen incremental gains by the Iraqi forces and the Kurdish forces," he said, while conceding that large swathes of Iraq remained out of the Iraqi government's control.
He said IS was not just terrorising Iraq and Syria "but is reaching out to Australia", making Australia's involvement in the conflict an issue of national security.
Australia joined the fight against IS last September and has already sent six F/A18 fighter jets, 200 special forces and 400 military support staff.
The Australian government estimates that about 90 Australian citizens are fighting with IS in Syria and Iraq and another 140 citizens in Australia are offering the group support.
The new training mission will be formally reviewed after 12 months.