China's online retail market registered total sales of 278.8 billion yuan ($44.5 billion) in the second quarter, up 45 percent year-on-year, according to domestic research company Analysys International.

The market keeps expanding at a fast pace despite the lackluster economic growth both in China and abroad.

Taobao.com and Tmall.com, both owned by e-commerce giant Alibaba Group, jointly held 76 percent of the market. In the second quarter, sales of the two websites exceeded 200 billion yuan, said Analysys International.

Alibaba expects the value of the transactions conducted on its two online shopping arms to hit 3 trillion yuan in the next three to five years, surpassing what Wal-Mart Stores Inc will record during the same period, said Zeng Ming, Alibaba's chief strategy officer, in an earlier interview.

Beijing Jingdong Century Trading Co, which runs 360buy.com, ranked second with sales of 15 billion yuan, representing 5.5 percent of the market. Tencent Holdings Ltd, China's biggest Internet company by sales volume, ranked third with 4.5 percent of the market.

E-commerce players have recently engaged in price wars to boost sales volumes this year amid fierce competition in the sector.