Claudio Descalzi noted the EU imports almost all the natural gas and most of the oil it needs, making it structurally dependent on foreign supplies.
"Europe needs to have what it hasn't got today, a structured and long-term energy security plan," Descalzi said in an interview published on Saturday.
"I don't think there will be problems with gas procurement, but it will cost more," he said regarding this winter.
Eni has strategic long-term gas supply contracts with a series of gas-producing countries including Russia.
Households across Europe face much higher energy bills due to surging wholesale power and gas prices, and consumer groups have warned the most vulnerable could experience fuel poverty.
Spain has urged the European Commission to devise guidance to help member states react consistently to power price spikes without testing the rules of the bloc.
Italy's Prime Minister Mario Draghi this week also said Europe needed to act to diversify its energy supplies and strengthen the bargaining power of purchasing countries to help curb power and gas price rises.
(Reporting by Giulio Piovaccari; editing by Jason Neely)