Mizuho Financial Group Inc. is considering buying an investment bank in Asia to help improve slow growth in winning equity and debt offerings in the region.

The lender's expansion plans may also include allying with an investment bank and purchasing asset managers and hedge funds in Singapore, India and Indonesia, Chief Executive Officer Yasuhiro Sato said in an interview. He also plans to increase the branches in Asia outside of Japan to 50 from 33 within five years for its corporate banking unit.

Mizuho isn't currently in talks with any banks for an acquisition or investment, he said.