BEIJING - The number of Chinese e-commerce customer complaints increased by 14.78 percent year on year in 2016, according to a report released by China's E-commerce Research Center (CECRC).

A total of 57 online retail shopping and service platforms as well as internet financial firms were involved in the complaints, which were related to product quality and delivery, customer service, exchange and return policies, and false promotions, the report said.

Of those complaints, product packaging and delivery complaints accounted for nearly 23 percent, while service complaints made up nearly 10 percent.

Complaints peaked following certain online shopping promotions, such as the Singles' Day shopping spree on Nov 11, the report said.

The retail sales volume of Chinese e-commerce hit more than 5 trillion yuan ($724 billion ) in 2016, 15.5 percent of which were social consumer goods, according to data released by China's Ministry of Commerce.

Authorities were urged to investigate and punish acts that disturb market order, enhance market supervision and provide legal provisions to protect consumers, the CECRC said.