That would change under a bill that forces manufacturers to declare where their oil comes from, meaning many famous brands would have to reveal, for the first time, that most of their "Italian" oil is actually from places like Spain and Tunisia.
"It's a con, pure and simple, like selling Gucci which isn't Gucci, or a Rolex which isn't a Rolex," said Massimo Gargano, head of Unaprol, the Italian olive producers' association.
Italy's olive farmers have convinced the government to change the current rules which allow oil to be labelled as Italian as long as it is blended in Italy even if, as is often the case, it has been trucked in from overseas.
Italy is both the biggest exporter and importer of olive oil, but its annual production, of around 650,000 tonnes is not enough to satisfy even domestic demand for the ingredient at the heart of the Mediterranean diet.
Unaprol estimates that only around 20 per cent of "Italian" olive oil is from olives grown in Italy.
The new bill, issued by Agriculture Minister Paolo De Castro, would mean labels have to state the country in which the olives were grown and where they are pressed. For blends, that means listing the various countries of origin.
The move has heartened Italy's olive producers, who hope to be able to charge a premium for genuinely Italian produce, but does not impress the companies which use the image of Italy to help sell olive oil blended, but not necessarily grown, here.
GUSTO
The changes would affect global brands which sell Italian virgin olive oil at a premium around the world.
"Wherever you are in the world, the Bertolli brand brings you closer to Italy," says the company's website. "Let Bertolli bring some Italian gusto' – a taste for life – into your home!"
Unilever, which owns the brand, says only 25-30 per cent of Bertolli oil is produced in Italy.
"It's not really about origin, for us it's about quality," said Trevor Gorin, spokesman for the Anglo-Dutch food giant. "We use Italian imagery in our advertising, it's more representative of the Mediterranean lifestyle than specifically Italian."
Another major olive oil brand, Carapelli, referred Reuters' questions to trade association Assitol, which represents Italy's vegetable oil industry.
"The draft as it stands, in our opinion, breaks European Union rules," said Assitol's Claudio Ranzani. "It contains excessively detailed requirements which would force companies to reveal trade secrets and constantly change their labels."
The European Commission could block the bill if it finds it breaks the principles of the EU's 27-nation single market.
"Whatever they do, (the law) would have to be in line with EU rules. That means it must not prevent the sale of oil which can be lawfully sold in other EU countries," a spokesman said.
Olive growers hope the new law will come into force within a year and look forward to cashing in on the "made in Italy" premium in a way only big brands have been able to do so far.
"If a consumer comes across a bottle which has on it Tuscan hills and cypress trees you can't then sell Moroccan oil," said GargaNo "A consumer should be able to buy Moroccan oil, if it says Moroccan oil."