The Greek bonds will not be eligible as collateral for the loans of the euro-system on a temporary basis, the European Central Bank (ECB) said in a statement on Tuesday.

The announcement came just one day before the second tender of a three-year term refinancing operation. The decision of the governing council of ECB has taken into account the rating of Greece, the statement said, referring to the downgrade by the rating firm Standard & Poor's (S&P) of Greece to "selective default" on Monday.

According to the statement of the ECB, the liquidity needs of banks can still be satisfied by relevant national central banks through emergency liquidity assistance.

The ECB also mentioned that the Greek bonds will become eligible as collateral once the collateral enhancement scheme agreed by the heads of eurozone state in July, 2011, together with a number of other measures aimed at assisting Greece in its adjustment program were implemented.

"This is expected to take place by mid-March 2012," said the statement.