China's online retail spending is expected to surpass $1 trillion by 2019, amid an increasing use of mobile phones for online shopping, according to estimates published by market research group Forrester.

Spending via mobile phones is expected to grow at a 44.2 percent compound annual growth rate over the next five years, twice as fast as online sales, which are seen growing at 19.9 percent CAGR, the latest Forrester report calculates.

The frequency with which online consumers in metropolitan China shop via their mobiles continues to show rapid growth, while residents in rural areas are using smartphones as their primary means of network access and for online shopping, Forrester said.

Factors like the addition of new products available online, an increasingly affluent middle-class and the convenience and fast delivery of online products will also contribute to the growth of the e-commerce industry over the next five years.

Chinese major online retailers, Tmall and JD.com are expected to continue dominating the e-commerce market in the coming years as they continue to improve their mobile investments and customer service experience.

"To capture the opportunities in the increasingly competitive retail market, organizations must realize the importance of digital capabilities" said Vanessa Zeng, senior analyst at Forrester Research. Tmall and JD.com currently hold 57 percent and 21 percent of the country's e-commerce market share.

China became the world's largest e-commerce market in 2013 with an online spending of $307 billion, outpacing the US market figure of $263 billion, according to the Forrester report.