"The eruption, a fountain of lava, lasted about an hour and happened in an uninhabited area," the spokeswoman told AFP by telephone from Catania, a town on the east coast of Sicily about 20 kilometres (12 miles) from Etna.
"We also saw two (lava) flows, one of which was very weak," she said, adding that they were proceeding down the mountain at a rate of about 10 metres (35 feet) per hour.
A small cloud of ash produced by the eruption is floating towards the Italian mainland, she added.
Mount Etna was last active in December, spewing clouds of ash and causing the closure of Catania airport for about two weeks.
The volcano, which is 3,295 meters (10,800 feet) high, had been dormant since July 2006.