HSBC Bank Plc has increased the size of its planned Samurai bond issuance to 117 billion yen ($1.3 billion), nearly double an initial estimate of Y60 billion yen, documents filed with Japanese financial authorities showed on Friday.

HSBC plans to sell its first-ever Samurai bonds later this month, with HSBC Securities (Japan), Mitsubishi UFJ Securities and Mizuho Securities acting as lead managers.

The bonds are expected to come in two tranches -- fixed-rate and floating-rate -- with a maturity of five years.

The bank will offer 87 billion yen in fixed-rate bonds, boosted from 30 billion yen in the initial plan, and 30 billion yen in floating-rate bonds, according to the documents.

Samurai bonds are yen debt issued in Japan by non-Japanese entities.

(Reporting by Rika Otsuka; Editing by Joseph Radford)