A volcanic island submerged off the coast of Sicily for the last 170 years could reappear in the coming weeks if furious seismic rumblings continue, Italy's chief seismologist said yesterday.

"We've seen Etna erupting, seismic activity to the north and east of Sicily and gas activity around the Aeolian Islands," Enzo Boschi, head of Italy's Institute of Geophysics and Vulcanology, told Reuters.

"The island could come back to the surface, but we'll have to wait and see... It could be a few weeks or months."

Formed by the tip of a submerged volcano, the island last popped up in 1831, sparking a diplomatic spat among several nations, before it sank beneath the Mediterranean waves six months later.

The volcano's peak now sits just eight metres under water about 30 kilometres south of Sicily, near Tunisia.

"We are monitoring things very closely," Boschi said. "The process could begin at any time... It would be a very beautiful and fascinating event."

Over the centuries, the island has emerged four times, with underwater volcanic eruptions first recorded during the first Punic War of 264-241 BC.

The last emergence on July 2, 1831, caused months of international wrangling with four nations making territorial claims including Britain, Spain and the Bourbon court of Sicily.

The rock, which rose some 65 metres above the surface and had a circumference of about five km, emerged for six months, giving the British time to claim it as Graham Island, while Sicily's King Ferdinand II called it Ferdinandea.

Scientists refer to it as Graham Bank, but Italians still call it Ferdinandea.

This time, Sicilian divers have gone down and planted a flag on the rock in the hope of claiming it as Italian the moment it rises above the surface, Boschi said.

While it may not spark the same diplomatic spat as 170 years ago if it emerges, there could well be a new claimant.

"I'm sure the European Union will want it as a member, won't they?" Boschi said.