Rudd quickly accepted the resignation, The Australian reported.
Fitzgibbon had been under fire for accepting two paid trips to China from Helen Liu, a businesswoman with ties to both countries. A small businessman and the only member of Rudd's Cabinet without a university degree, Fitzgibbon also had to deal with complaints he was not qualified for one of the most important Cabinet posts and admitted himself that his appointment was an "absolute surprise".
A senior defense official told the newspaper Fitzgibbon did better than expected.
"He cut through with NATO and gained access for Australia to planning documents for the war in Afghanistan, formed a genuinely warm and productive relationship with his U.S. counterpart, Secretary for Defense Robert Gates, and was quick to introduce a long-overdue drive for savings, efficiency and accountability in Defense and the (Australian Defense Force)," he said.