Simply titled "Allegro Molto," the piece was found recently in a notebook in the attic of a private home in Austria's Tyrol province.

Just a few minutes long, the piece is believed to have been composed in 1767 or 1768, but was later transcribed into this notebook, which is dated 1780, music expert Hildegard Herrmann-Schneider told a news conference.

"The name 'Del Signore Giovane Wolfgango Mozart' is incredibly clear," added Ulrich Leisinger, director of research at Salzburg's Mozarteum foundation.

This convinced researchers that the piece was indeed by the young music genius, even though the writing did not belong either to Mozart or his father Leopold.

It is thought to have been transcribed into the notebook by a close relative or friend.

Only Leopold Mozart used this name when writing down his son's compositions, according to Herrmann-Schneider, who found this latest piece while doing research work.

"It was a very lucky find," she said.

The 160-page notebook also contained several compositions by Leopold Mozart but only one by his son.

Austrian musician Florian Birsak, who performed the piece Friday on Mozart's own fortepiano, noted: "It's not just anyone's piece, there is already a touch of the great Mozart he later became."

This is not the first time a Mozart composition has been rediscovered in recent years. In 2006, one was found in the archives of the Salzburg archbishopry, and in 2009 in the Mozarteum's own archives. (AFP)