The troops will replace those currently providing security for Japan's non-combat forces, which are aiding Iraq's reconstruction in the southern city of Samawah, The Australian reported.
The Australian troops will also assist in the training of Iraqi soldiers.
The Japanese government is expected to announce the withdrawal of its forces within six months. In that case, Nelson said, his troops would be redeployed "in the cause of supporting Iraqi security and democracy."
There are currently 470 Australians based at Camp Smitty outside Samawah. The first group was deployed in May last year, and the second at the end of the year.