Prime Minister Tony Abbott won’t put a time limit on Australia’s commitment to the fight against Islamic State extremists, saying its deployment to the Middle East could last “many, many months”.

Combat aircraft and special forces advisers will be sent to the United Arab Emirates as part of an international coalition after a specific request for support from the US government.

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Asked if Australia had an exit strategy for the deployment of the 600 military personnel, Mr Abbott said: “I’m not going to put a time limit on it.”

“It’ll certainly be months rather than weeks, and quite possibly many, many months,” he told the Nine Network.

The prime minister has said the deployment does not mean Australia is going to war in Iraq, with a decision yet to be taken to commit to combat operations against IS militants.

However, on Monday he defended the decision.

“This is a fundamentally humanitarian mission that is designed to protect people in Iraq from the murderous rage from this ISIL movement,” he said.