CAIRO, Dec 14 (Reuters) - Egypt's central bank said on Wednesday that high-interest deposit certificates issued by banks since the pound currency was floated last month have so far attracted 64 billion Egyptian pounds ($3.47 billion) in new investment inflows.

Egypt's two largest state-owned banks offered 18-month certificates of deposit at 20 percent and three-year certificates of deposit at 16 percent in a bid to attract currency being held outside the banking system.

($1 = 18.4500 Egyptian pounds)

(Reporting by Ehab Farouk; Writing by Eric Knecht; Editing by Catherine Evans) ((eric.knecht@thomsonreuters.com; +20 2 2394 8102; Reuters Messaging: eric.knecht.thomsonreuters.com@reuters.net))