AUSTRALIAN special forces soldiers will be ready to hit the ground in Iraq once a legal agreement between the two countries is finalised.
It is understood up to 200 SAS soldiers could be on the ground within a week.
Prime Minister Tony Abbott said on Tuesday their main mission would be to advise and assist Iraqi forces in their fight against Islamic State forces.
"It will not just be of benefit to the people of Iraq, it will be of benefit to everyone all over the world because ISIL is a death cult," he said.
"It is not Islamic. It is an affront to civilised people everywhere regardless of their religion, ethnicity or culture.
"It is a death cult that has declared war on the world and it is important it be appropriately resisted."
Mr Abbott said an agreement between the two governments was expected, but he was not prepared to put a time limit on how long it would take.
"We have written to the Iraqis, the Iraqis have written back to us and we now need to consider their response and finalise our considerations," he said.
"It is absolutely imperative for the world that we disrupt and degrade the operations of ISIL which is an assault not just on a country but on civilisation."
Mr Abbott ruled out any tax increases or tax hikes to pay for the conflict, which is expected to cost taxpayers more than $500 million annually.