Warren Truss, who is acting prime minister while Tony Abbott is in Papua New Guinea, told reporters that "nothing of particular significance" had been identified in Friday's search.
Five planes were sent to look for objects that may be from the missing Malaysian jet, and an Australian official said the hunt would be extended for another day.
The search is part of an international effort to solve the nearly 2-week-old mystery of what happened to the jet, which disappeared with 239 people aboard.
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