The Greek electoral system .

The electoral system used is referred to as "reinforced proportionality", a form of semi-proportional representation with a majority bonus: The party that wins a plurality of votes cast is awarded an extra 50 seats. Small parties on the other hand need to reach an electoral threshold of 3% in order to be represented in parliament. These provisions help the party or coalition that wins a plurality to achieve an absolute majority (151 out of 300 parliamentary seats); this is intended to enhance governmental stability.

The current electoral law was used for the first time in the May 2012 election. It reserves 50 parliamentary seats for the party or coalition of parties that is supported by a plurality of votes cast. If the largest party or coalition has won at least 40.4% of the vote, these extra reserved seats will be sufficient to ensure it a majority in parliament. The remaining 250 seats are divided proportionally according to each party's total valid vote percentage; this is slightly higher than the raw percentage reported, as there is always a small number of invalidated or "blank" votes (usually less than 1%), as well as the percentage of smaller parties that fail to surpass the 3% threshold, all of which are disregarded for the purpose of seat allotment. The previous law (used in the 2009 legislative elections) was less favorable for the plurality party, as only 40 additional seats were reserved for them.

A rather complicated set of rules deals with rounding decimal results up or down, and ensures that the smaller a constituency is, the more strictly proportional its parliamentary representation will be. Another set of rules apportions the 50 seat premium for the largest-tallying party among constituencies. Individual seats are apportioned by "cross of preference". Voters mark a cross next to the name of the candidate or candidates they prefer, the number of crosses varying from one to five depending on constituency size. Ballots with no crosses or more crosses than allowed, count for only the party but not the individual candidates.

Tallying is done manually in the presence of representatives of all contesting parties. Party tallying, which is easier, is done first so that returns may be announced quickly. Individual candidate tallying is done next and can take several days. Once the number of seats per party and constituency is determined, the seats are filled on a top-down basis from the individual cross-of-preference tallies. Party heads and acting or past Prime Ministers are exempt from cross-of-preference voting: they are automatically placed at the top of their party list and are elected, provided their party achieves at least one seat in the particular constituency.

By constitutional provision, the electoral law can be changed by simple parliamentary majority, but a law so changed comes into effect in the next-but-one election, unless a two-thirds parliamentary supermajority (200 or more votes) is achieved. Only in the latter case is the new electoral law effective at the next election. A case in point is the current electoral law, which was passed in 2007. Because this law was passed by a simple majority, it was not used for the subsequent 2009 election, but was then used in the 2012 election.

Greek electoral laws since 1974
Law's "trademark"Passed inPassed byApplied in (election year)Approximate nationwide vote percentage needed for an absolute majority of seats in Parliament for the first-past-the-post partyThreshold
Reinforced proportionality 1974 New Democracy '74, '77, '81, '85 (the premium of seats was reduced) in almost any case (40% and a clear advantage were necessary in '74 elections) none for the first seat allocation (in prefectures), but 17% for the second one in peripheries (this threshold was not in force during '85 elections)
Simple proportionality 1989 Panhellenic Socialist Movement '89 (June), '89 (November), '90 47%+ none
Reinforced proportionality 1990 New Democracy '93, '96, '00, '04 in almost any case 3%
Reinforced proportionality 2004 Panhellenic Socialist Movement '07, '09 41.5%+ 3%
Reinforced proportionality
(current)
2007 New Democracy '12 39%+ 3%

 

(source- wikipedia)