By Ehab Farouk

CAIRO, March 22 (Reuters) - The National Bank of Egypt will issue a dollar-denominated bond on international debt markets by the end of June, in order to diversify its sources of foreign currency, the bank's chief executive told Reuters on Sunday.

Hisham Okasha, CEO of the country's oldest lender, did not specify the exact size of the issue, but said in a telephone interview that it would be in the range of an issuance in August 2010 that was valued at $600 million.

The interest on that issuance was 5.25 percent.

The aim of the new bond issuance is "diversification of sources of hard currency for the bank", Okasha said.

National Bank of Egypt, which is the country's largest state-owned bank, will invite 13 international financial institutions to compete to arrange the bond issue, he said.

A successful deal could encourage a number of Egyptian banks and companies, which face a shortage of hard currency and have been shut out of international debt markets since 2011, to attempt their own transactions. (Reporting by Ehab Farouk; writing by Shadi Bushra; editing by David Clarke and Susan Thomas)