According to CNN reports, the objects are indistinct but of "reasonable size" the largest about 24 meters long (79 feet).
John Young, general manager of emergency response for the Australian Maritime Safety Authority said if the piece of the plane is that big, it could be it's the tail section.
However he warned that the size gave him a degree of concern,
"It's a big piece of aircraft to have survived something like this." He said.
The announcement has raised hopes of finding parts of the plane amid a huge search that is now in its 13th day.
Previous reports of debris found in the sea haven't turned out to be related to the passenger jet, which vanished over Southeast Asia on March 8. CNN reports.