Users of Vivo Nex found the phone's camera moving upside down when they were using QQ browser, an application made by Tencent.
The smartphones have nothing to do with Tencent and this problem was not detected in other phones.
"It feels like being spied on by a little eye, and felt weird," users were quoted by China Consumer Journal as saying. Many users were also concerned that the application was secretly taking pictures or even filming them.
QQ browser said on Thursday that the camera does move, but that it would not activate the camera or take pictures or videos. "QQ browser will not violate users' privacy," the company said in a statement.
The company explained that due to some technical problems, the camera moves. "We are sorry for causing confusion, and we will improve our users' experience and warn them beforehand," it said.
China Consumer Journal said that many applications have access to users' sensitive information, such as their frequently visited sites and contact lists.
The Ministry of Industry and Information Technology published a list in early 2018, which includes 46 applications that collect users' personal information without their approval and automatically send messages without informing users, Beijing Youth Daily reported earlier this month.
"The users' information can be easily compromised on the internet, and the most dangerous part is the information could be illegally used," Wang Sixin, a media law professor at Communication University of China, told the Global Times on Friday.
A total of 6.05 billion pieces of personal information were leaked in 2016, up 9.4 percent from 2015, Chinese internet security company Qihoo 360 said in March, 2017.
An average of 16.9 million pieces of information were leaked from the 359 internet loopholes detected by its security monitoring website Butian.
It is difficult to track where users' personal information end up, Wang said, and he urged the government and companies to better protect netizens' information.
Guo Qiquan, chief engineer at the network security safeguard bureau of the Ministry of Public Security (MPS), said on Monday that China is expected to issue a regulation on graded protection of cyber security, and that "the biggest change" in the new regulation is it increases the protection level for both individuals and institutions.