BEIJING - Staggering sales by Chinese online vendors are evidence of robust consumption, but experts also warn that online commerce needs to address problems in order to sustain growth.

Alibaba's Tmall's online sales on Thursday, Singles Day, grew 60 percent to reach 91.2 billion yuan ($14.3 billion). The second-ranking JD.com, though much smaller in volume, said 32 million orders were placed on Thursday, up 130 percent from last year.

JD.com's multi-day shopping campaign from Nov 1 to 11 saw 100 million orders, up 140 percent from last year.

Experts say the huge volume, along with growth in rural e-commerce, global reach, and online-to-offline connections, are trademarks of this year's Singles Day sales.

"Compared with slow and sapping consumption in North America, Europe and even Japan and the Republic of Korea, China's domestic consumption market is huge, and online shopping power is really a gold mine," said Zhang Yi, CEO of IImedia Research, which analyzes online commerce data.

From January to September, China's total retail sales of consumer goods grew 10.5 percent year on year to reach 21.6 trillion yuan ($3.4 trillion). Online sales grew 36.2 percent and reached 2.6 trillion yuan. According to China's new five-year plan, consumption should play a fundamental role in China's future economic growth.

However, the bulk of Singles Day sales may have been transferred from offline sales, said Cao Lei of the China Online Commerce Research Center.

"Though growing at a robust rate, China's online commerce is still at the beginning stage. Online shopping platforms need to think beyond the membership model to meet growing shopping demand," Cao said.

In addition, backlogging, counterfeit and poor after-sale service are problems that need to be solved by online merchants, Cao added.