Olive oil has become the most stolen product in supermarkets across Spain as organized crime gangs target "liquid gold" to sell on the secret market, new figures show.

According to the Financial Times, olive oil is currently the most stolen product in regions that make up 70% of the country's population.

Supermarkets chain large five-litre bottles of olive oil together and padlock them on shelves to prevent theft, while other stores attach security tags to the bottles that must be removed by staff.

Spain is the world's largest olive oil producer. However, stocks were almost depleted in Europe after extreme weather conditions damaged harvests for the second year. Global production is expected to fall to 2.4 million tonnes, less than last year's harvest and well below global demand of around 3 million tonnes, according to the International Olive Council.

Prices in Spain have more than quadrupled in the last four years. Consumers who four years ago paid less than 5 euros for a liter of high-quality extra virgin olive oil are now seeing prices rise as high as 14 euros.

Alejandro Alegre, marketing manager at security company STC, which investigates supermarkets, told the FT that these thefts were carried out by organized gangs trying to profit from famine, not hunger.

In December, police in Spain and Italy arrested 11 people and seized more than 5,000 liters of adulterated olive oil after dismantling an international gang that allegedly tried to make a profit by selling cheap oils at a higher price.

Alegre said it was unusual for a staple food item like olive oil to rank so high on the theft list.