Italian energy firm Eni has found a massive new natural gas field, which could be one of the world’s largest.

The company says the field is off the coast of Egypt, in an area 1,450 metres beneath the surface, covering over 100 square kilometres.

Eni says it holds as much as 30 trillion cubic feet of gas, the equivalent of about 5.5 billion barrels of oil.

It has been named the ‘Zohr field’, and Eni says it “could become one of the world's largest natural-gas finds” filling Egypt's gas needs for decades.

“This historic discovery will be able to transform the energy scenario of Egypt,” said Claudio Descalzi, chief executive of Eni.

Eni is the biggest foreign energy firm in Africa, and has full rights to the area,

The find came after it signed an energy exploration deal with Egypt's oil ministry in June this year.

The $2 billion deal let the company explore in Sinai, the Gulf of Suez, the Mediterranean and areas in the Nile Delta.

It is the latest in a string of big gas discoveries in the Mediterranean, including by Egypt's neighbour Israel.