The study, collating existing scientific data, says that geological similarities indicate that reserves offshore Crete may match the prolific Levantine Basin where recent Israeli and Cypriot discoveries are clustered.
It points to strategically significant reserves in Greek waters south of Crete in the range of 3.5 trillion cubic metres (Tcm), enough to cover over six years of EU gas demand, and the equivalent of about 1.5 billion barrels of oil.
While it will take years to explore and develop any offshore gas sector, Greece has launched a licencing round and has commissioned a seismic survey company to pin down the extent of hydrocarbon deposits. The results are expected in mid-2013.
Presenting their findings, study authors Antonis Foscolos, Elias Konofagos and Nikos Lygeros said they expected the reserves to generate €464 billion in state earnings over 25 years.
"We feel this is a very conservative figure," Konofagos, whose Athens-based company Flow Energy informally advises the government on energy strategy, told Reuters.
Foscolos, professor emeritus at the Technical University of Crete and the Canadian Geological Survey, said that subsea methane emissions and the presence of gas hydrate mounds on the seabed indicate the presence of large reservoirs.
Another study published in the Journal of Environmental Science and Engineering in June estimated that Greece had 4 Tcm of gas and a further 3 billion barrels of crude oil.
Taking into account savings from fuel imports - Greece spends 5% of GDP on energy imports - discoveries on the scale envisaged could clear the country's debt and bring billions in annual cost savings.
Europe's gas hub?
With its potential wealth, Greece could also become a transit hub for gas to Europe if it establishes an exclusive economic zone allowing it to legally extract hydrocarbons, which it currently lacks south of Crete and in other areas.
The head of the ITGI pipeline, which lost out in the race to carry Caspian supplies to Europe, hopes to convert his project into a conduit linking East Mediterranean discoveries with the gas-thirsty continent.
Despite high hopes, geologists caution that estimates alone mean nothing, and that only drilling can determine the facts.