The former head of ESB International says Ireland is "very poorly prepared" for gas shortages because of a lack of gas storage.
Don Moore also said that Ireland had chosen to "follow a very risky route" by not building an import facility for liquefied natural gas.
Speaking on Today with Claire Byrne, Mr Moore said that while Germany has 100 days of gas storage, Ireland has none.
He said while the country had the opportunity in the past to create storage "we chose not to do it".
He described Ireland's decision not to build an LNG terminal off the Irish coast as "quite extraordinary".
"We don't have any gas storage in Ireland, which is quite unusual because nearly every other European country has gas storage," Mr Moore said.
"We could have used the Kinsale field for gas storage, which we chose not to do. It would have cost money but that was a decision," he added.
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He said that because Ireland is on the end of the European gas grid, just 30% of gas used in Ireland is produced .
Ireland relies on external sources for the other 70% of supply which, he said, left the country very poorly prepared for any shortage of supply this winter.
"We're probably the only country in Europe with a coastline that decided not to have an LNG import facility," Mr Moore said.
Mr Moore also warned that any shortage of gas could also impact on electricity supply.
"One of the problems I think the public needs to understand is that gas makes up a key component of our electricity system," he said.
"We have 5,000 megawatts of renewable energy but when the wind doesn't blow, that renewable energy doesn't generate any electricity," Mr Moore said.
"For backup, we depend on gas-fired power stations, so they need gas. If gas was rationed it could affect the electricity supply, which would be a pretty catastrophic situation. Not just for the public but for industry as well," he added.
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Mr Moore also described the situation in Germany, which has said today it is unsure if the NordStream 1 pipeline will be turned back on after a planned annual 10-day maintenance period, as "serious".
"The news this morning from Germany is actually very serious in that they're planning for a scenario where Russia actually cuts off gas during the winter, just to make it more difficult," he said.
"They're preparing plans, for example, using sports halls during the winter so that people can go there and get warm if their central heating gas is cut off. So we're facing a situation now that no one ever envisaged a year ago," Mr Moore added.
The head of Germany's energy regulator said it does not know when or if the gas supply will resume.
Klaus Mueller said: "What happens at the end of the maintenance, nobody is able to say at this moment. We won't know any time sooner than a day before its scheduled end."
He added: "Should there be a gas emergency we will take differentiated decisions on large gas consumers but this will only be possible from October, based on an IT platform. We would look at economic damages, economic consequences, the impact on supply chains and social dimensions.
"All this will be looked at from autumn. Up until then, we can unfortunately only take proportional decisions, or rather point by point individual decisions."
