Making use of provisions under a 2008 law which aimed to help banks with liquidity during the global credit crisis, the group issued a total of 200 million new preferred shares which were fully taken up by the government.

Greek lenders are trying to cope with rising bad debts and a shrinking deposit base as the austerity-hit country struggles through its fourth straight year of economic contraction, seen topping 5.5 percent in 2011.

Banks are expected to have to recapitalise after writedowns resulting from a planned bond swap agreed in October, which calls for a 50 percent nominal writedown on Greek government bonds.

NBG said the capital increase strengthened its capital adequacy ratios by 1.5 percentage points, bringing its Core Tier 1 ratio to over 11 percent, based on end-September data.

The bank had only tapped 350 million euros under the scheme out of a total of 1.35 billion it had been allocated.

It said its fully paid share capital now stands at 6.138 billion euros, divided into 965,090,482 common shares with a par value of 5 euros, 25 million non-voting preferred shares with a par value of 0.3 euros each and 270 million redeemable, preferred shares under the liquidity enhancing law of 2008 which have a par value of 5 euros each. (Reporting by George Georgiopoulos)