TUNIS, June 28 (Reuters) - Tunisia's central bank has kept its key interest rate unchanged at 4.25 percent, an official in the bank said on Tuesday.

The bank last cut its main interest rate in October from 4.75 percent, in a bid to boost economic growth as inflation fell.

(Reporting By Tarek Amara; Editing by Janet Lawrence) ((tarek.amara@thomsonreuters.com;))