Brendan Nelson told the Australian Broadcasting Corporation that Iraq was "an important supplier of energy, oil in particular, to the rest of the world, and Australians ... need to think what would happen if there were a premature withdrawal from Iraq".
The Australian prime minister, John Howard, rushed to play down Mr Nelson's comments, which threatened to reignite anti-war protesters' claims that the 2003 invasion was more a grab for oil than a bid to destroy Saddam Hussein's weapons of mass destruction, which proved to be non-existent.
Australia maintains 1,000 troops in Iraq, supported by 600 air force and navy personnel in the region.