The statues, dating to roughly 1350 BC, were damaged in an earthquake during the Roman era.
The colossi are some of Egypt's oldest tourist attractions, drawing visitors since ancient times.
The twin statues, over 18 metres (60ft) tall each, are of Pharaoh Amenhotep III, who was worshipped as a deity.
The statues are the only remains of a large temple that was built in memorial of the pharaoh.
The team made the discovery in co-operation with archaeologists from Egypt's ministry of antiquities, Mohammed Ibrahim said.
He said the pieces belong to the belt of one statue and the base of the other.