Mr Shorten returned from the unannounced visit to the Iraq base on Wednesday, having been briefed by Australian command and the Head of Mission in Iraq on operations in the region.
He also thanked Prime Minister Tony Abbott for helping arrange the low-key visit.
“I was humbled by the men and women I met at both the Australian Force base in the Middle East Region and in Baghdad - their dedication, skill and sense of purpose,” he said.
“I conveyed Federal Labor’s bipartisan support for the current mission in Iraq to the personnel on the ground, and our thanks for their service and their sacrifice.
“I also assured them that their families were in our thoughts and would always be looked after while they were on deployment.”
Australia has about 200 soldiers in Iraq, members of the 2nd Commando Regiment who are advising Iraqi units in their fight against IS.
Mr Shorten said all Australians should be proud of the work they were doing to defeat IS and enhance capabilities of Iraqi Security Forces.
