Yu'E Bao (Leftover Treasure), an Alibaba personal finance product, had 43.03 million users with aggregate deposits of 185.3 billion yuan ($30.4 billion) at the end of 2013. [Photo/icpress.cn]

Alibaba Group Holding Ltd, the Chinese mainland's largest e-commerce firm, has joined with Octopus Holdings Ltd, a subsidiary of the Hong Kong subway giant MTR Corporation Ltd, in a bid to expand its e-pay business in Hong Kong.

The newly launched service would be first such in Hong Kong to allow users to pay online with the support of Near Field Communications technology, Octopus said in a statement, adding that consumers could shop with the new app on smartphones and tablets on Taobao, the Chinese mainland's largest e-commerce website that is owned by Alibaba.

Alipay, the e-pay system of Jack Ma's Alibaba Group, has gained a foothold in the city since it made a foray into Hong Kong’s physical retail business. Alipay has also surpassed Paypal as the world's top mobile payment platform, with bills paid by mobile phone surging to 900 billion yuan ($148.4 billion) in 2013.

Alibaba has been expanding aggressively before its hotly anticipated initial public offering.

Octopus, the provider of value-stored smart cards used by 1.3 million Hong Kong residents, has also extended its business on the Chinese mainland in recent years, and has been widely accepted in the nearby Guangdong province.

Don't miss:

Alibaba taps into language-learning biz

Alibaba: New kid in US e-commerce