The partnership with NETSTARS, a Tokyo-based mobile payment technology company, will allow travellers to use their home mobile wallets on Singtel's VIA network to pay digitally at stores in Japan - a popular destination for Southeast Asians.

Singtel, Southeast Asia's largest telecom operator, is keen to expand beyond its traditional carrier services into areas such as digital marketing, cybersecurity, mobile payments and video streaming.

Southeast Asia, where a chunk of the 650-million population is underbanked, is becoming a crowded market for mobile payments. Singtel wants to stand out by permitting users to be able to pay with their e-wallets outside their home country.

Singtel plans to expand the mobile wallet alliance to India, the Philippines and Indonesia.

"With scale we will, over time, be able to convert payments into multiple uses," said Arthur Lang, CEO of Singtel's International Group, adding the company could look to provide more financial services.

Singtel's Thai associate Advanced Info Service Pcl (AIS) is part of VIA network; and it recently signed an agreement with the digital services arm of Malaysia's Axiata Group Berhad.

Including its regional associates, the telecom operator has a mobile customer base of over 675 million.

(Reporting by Aradhana Aravindan, Editing by Sherry Jacob-Phillips)