"With these deployments, Australia demonstrates its continued leadership and resolve in addressing the urgent and critical security challenges that threaten Australia, its people, and the broader international community," White House spokesman Josh Earnest told reporters on Air Force One.
"Australians and Americans have fought alongside each other in every major conflict over the past century, and we are grateful for Australia's further contribution," Earnest said.
Australia's cabinet earlier authorised the deployment of special forces and military air strikes to tackle the Islamic State organisation in Iraq, Prime Minister Tony Abbott said.