Australia captain Michael Clarke is "hopeful" he will be fit enough to return to action for his side's ICC Champions Trophy clash with Sri Lanka later today.

The 32-year-old has missed both of Australia's games so far with a back injury as they were defeated by England and had their clash with New Zealand abandoned.

"I'm hopeful, no doubt about that, but I really have to wait to see how I pull up tomorrow morning after training again today," Clarke told reporters. "My back is certainly improving, which is a positive."

Australia need to beat Sri Lanka by a huge margin to reach the last four to overtake New Zealand in second place in Group A and have a chance of retaining their title.