A 2,000-year-old gladiator helmet will be a centrepiece of an exhibition of the Roman city of Pompeii at the Melbourne Museum.

The museum will open its 'A Day in Pompeii' exhibition on June 26 and on Thursday it gave media a preview of a helmet that has travelled all the way from Naples to be part of the show.

The helmet - made of bronze - was worn at Pompeii's amphitheatre by a heavily armoured gladiator called a murmillo.

With more than 250 objects - many never shown before in Australia - the exhibition tells the story of life in the ancient city, from food, dining, shopping, medicine and religion.

"No other ancient city has been found so complete and intact," Melbourne Museum CEO Dr Patrick Greene said.

"The architecture, art and personal belongings recovered from Pompeii providing an unparalleled record of what life was like in the Roman Empire."

The Roman city of Pompeii was buried by the catastrophic eruption of Mount Vesuvius on August 24, AD 79. The city was preserved under thick volcanic ash until it was rediscovered by archaeologists in the early 1700s.

AAP