China's online shopping sector was the largest target of consumer complaints in the service industry in 2013, according to two consumer rights groups.

The China Consumers' Association said online shopping, Internet access and mobile telecommunications received almost half of all consumer complaints in the sector last year.

Online services, especially shopping, also topped complaints received by the China Association for Quality Promotion, which focuses on protection of consumer rights.

A report released by the China National Institute of Standardization on Wednesday said intense competition in the industry has failed to yield improvements in service standards.

"The high number of consumer complaints is in line with the country's fast-developing e-commerce market, which is the world's largest in terms of the number of participants," said Wu Jingming, a professor of consumer rights law at China University of Political Science and Law.

Wu said the online shopping industry was built on the framework of industry self-regulation and without guidelines and regulations from authorities.

"That means there is more room for activities that infringe upon consumer rights and consumers cannot solve the disputes through traditional channels. All they can do is to file complaints and seek help," he said.

Wu said the solution is increasing the penalties for infringing consumer rights.

Around 20 percent of consumers failed to protect their rights under a new law that gives them seven days to return goods for refunds, and more than 30 percent of respondents said online shopping platforms failed to provide accurate contact information for the sellers, according to a survey by the China Consumer's Association in April.

Wu said the country needs a law exclusively for the e-commerce industry.

The number of consumer complaints received in the medical and health sector, clothing and beauty industry, finance and insurance and tourism by the China Association for Quality Promotion tripled last year.

Tang Wanjin, vice-president with the China National Institute of Standardization, said the fact that the country's service sector is mostly small and medium-sized companies has hindered the improvement of standards.

"Meanwhile, the country is lacking a quality system in the service sector to push for the improvement of services," he said.

As of 2012, China had 7.22 million companies in the service sector, according to CNIS.

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