Scientists made the startling discovery while carrying out research into the historical eruption patterns of the Alban Hills volcanic complex over the last 600,000 years.
“The surprising results reveal these volcanoes are anything but extinct,” explained INVG geophysicist Fabrizio Marra, who studied the hills with colleagues from Rome's Sapienza University.
“They are moving out of a dormant state and are waking up.”
Having shown no sign of activity for the last 36,000 years, the lush green Alban Hills are today a popular spot for day-tripping Romans, located just 20 kilometres south of the capital.
Scientists say the long-empty magma chambers beneath the volcanic hills are once again filling up with red-hot gasses and molten rock.
A number of indicators have confirmed the findings, including recent satellite data which show the hills are rising up by 2-3mm each year due to the build-up in pressure below the ground.
Geological cracks and fissures in the area also show signs they have expanded considerably over the last 2,000 years - the blink of an eye in geological terms.
“We will now need to closely monitor the volcanic area for the foreseeable future,” explained Mara.
But while it has been confirmed that volcanic activity is on the rise, experts say lava won't be spilling from craters in the Alban Hills anytime soon.
“It's difficult to say when another eruption could happen, but we are probably talking about a thousand-year time period,” Mara said.
Historically, eruptions have occurred in the area once every 40,000 years.