The world's top cell phone maker Nokia has bought a minority stake in Obopay, enabling the U.S. mobile money firm to extend its product offering and geographical presence.

This investment reflects our belief in the global potential for mobile payments, Teppo Paavola, head of Corporate Business Development at Nokia, said in a statement. The size of the investment was not disclosed.

Research firm Berg Insight expects the number of people using mobile financial services to grow on average 89 percent a year to 913 million in 2014 from just 20 million last year.

Mobile banking services are expected to match those of online retail banking and eventually go beyond that with technologies like near-field communications (NFC), which enables payments by just waving a phone. (Reporting by Tarmo Virki; Editing by Hans Peters)