The European Union's executive Commission says membership in the euro bloc is "irrevocable" but leaves it open to what extent Greece could renegotiate the terms after the Jan. 25 elections.

EU spokeswoman Annika Breidthardt said Monday that if the Greek elections call for a need to look again at the conditions of Athens' membership within the 19-country eurozone, "we will deal with that once the Greek voters have cast their verdict."

At the same time, she insisted that a full exit by Greece was not on the cards since the euro rules say that "membership is irrevocable."

Some say that if the left-wing Syriza party wins the election in Greece, the new government may renege on the terms of the country's bailout, possibly putting in question its euro membership.