A bird-like statuette dating back 7,000 years has mystified archaeologists in Greece who still do not know exactly what it is, or where it came from.

The "7,000-year-old enigma," as it has been dubbed by the National Archaeological Museum, has been put on display until March 26 after being brought from the museum's storerooms.

It is the latest item to be presented under the title "The Unseen Museum" - a reference to the roughly 200,000 antiquities from statues to gold jewelry and every-day objects in store and not on daily display.

Carved out of granite, the 36 cm (14 inches) "enigma" statuette of the late Neolithic era has a pointed nose and long neck leading to a markedly round belly, flat back and cylindrical stumpy legs.

"It could depict a human-like figure with a bird-like face, or a bird-like entity which has nothing to do with man but with the ideology and symbolism of the Neolithic society," Katya Manteli, an archaeologist with the museum, told Reuters.

Experts also cannot be sure of its provenance, as it belongs to a personal collection. They assume only that it is from the northern Greek regions of Thessaly or Macedonia.

Unlike most Neolithic figurines made of soft stone, it is carved out of hard rock even though metal tools were not available at the time.

And while it is too short for a life-size depiction of the human figure, it is bigger than most Neolithic statues, which are rarely found over 35 cm tall.

"Regarding technique and size, it is among the rare and unique works of the Neolithic period in Greece," Manteli said.

More puzzling still is the lack of clear indication of sex. Is it due to technical sculpting limitations? Or did the sculptor intend to create an asexual figure. Archaeologists believe the fact that the statuette is polished suggests the figure is in its final form, although they maintain that if the sculptor had the appropriate tools it would have taken a more specific form.

"Yes, it could be a pregnant figure but there are no breasts, used in Neolithic times to depict the female body. On the other hand it lacks male organs so it is presented as an asexual figure," Manteli said.

"There are enigmatic aspects to it which make it charming."