"Obviously the Middle East itself, not only Iraq but the entire region, is an important supplier of energy, oil in particular, to the rest of the world," he said.
"Australians and all of us need to think what would happen if there were a premature withdrawal from Iraq.
"It's in our interests, our security interests, to make sure that we leave the Middle East, and leave Iraq in particular, in a position of sustainable security."
Australian prime minister John Howard was quick to downplay the remarks - saying that it was "stretching it a bit" to conclude oil was the country's only motivation for staying in Iraq.
"We didn't go there because of oil and we don't remain there because of oil," he said, in an interview with a local radio station.
"A lot of oil comes from the Middle East - we all know that - but the reason we remain there is that we want to give the people of Iraq a possibility of embracing democracy."
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