Greek leftist opposition party Syriza holds a steady lead over ruling conservatives with days of campaigning left for Prime Antonis Samaras to try to close the gap before a snap election on Jan. 25.

Financial markets are nervous a Syriza victory could trigger a standoff with EU/IMF lenders that results in Greece leaving the euro zone.

"First of all it is not allowed under the rules of the euro area, and secondly I think it would be devastating for Greece," Lagarde told Irish state broadcaster RTE when asked if an exit by Greece would be devastating for the euro zone.

(Reporting by Conor Humphries; Editing by Bernard Orr)