They accounted for 41 percent of customer complaints followed by telephone and telecommunications (19 percent) and electronics (7 percent), the Vietnam Competition Authority under the ministry said

"We notice an increasing number of online loan services companies. These models are expanding and increasing rapidly in terms of both number of customers and value of disbursements, thus leading to an increase in complaints."

The Vietnam Competition Authority said it answered 5,186 out of 9,295 calls its call center received last year, 1,422 of them being violations of consumer rights and requests to resolve them.

Around 34 percent of all complaints related to consumer information protection, mainly about businesses illegally collecting consumer information and not correcting information on customers' request, which led to continuing usage of the information, it said.

The most frequent other complaints pertained to contracts with service providers (20 percent), information provided by sellers (17 percent) and goods quantity, quality and delivery time (14 percent).