A young online retailer contacts with buyers at home in Chongqing. [Photo/VCG]

China's 2017 online retail sales is approaching $1 trillion that will buttress the country's position as the largest e-commerce market in the world, S&P Global Ratings said on Monday.

The rating agency said the estimation is based on record online spending during the country's Singles Day shopping carnival last Saturday. Driven by that, China's online retail industry's annual growth will be 20-25 percent in next 12-24 months.

According to Syntun, a Beijing-based e-commerce data provider, the online sales totaled 254 billion yuan ($38.26 billion) at this year's event.

The huge number of transactions last Saturday indicated that Chinese online retailers still have enough space to grow, financial news portal stcn.com said quoting Shalynn Teo, an analyst at S&P.

More product categories will go online, and the increasing mobile penetration will promote the online sale momentum, Teo said.

In addition, purchasing online will become more popular in China's third- and fourth- tier cities and rural areas, the analyst added.

China's online retail sales surged 34 percent year-on-year to 5.54 trillion yuan in the first 10 months of this year, surpassing the 10.3 percent increase in overall sales of consumer goods, official data showed on Tuesday.

In next 12-24 months, the intense competition will put pressures on the Chinese online retailers, Teo warned, adding that the pricing power in addition to rising marketing and delivery expenses will lead the industry's margins to slip.

"But higher growth and improving operating leverage will ease the risks," Teo said.