Internet users in Beijing have been told they do not need to change their Wi-Fi passwords despite reports of a vulnerability in the encryption system.

TechCrunch, a US news website, reported on Tuesday that security researcher Mathy Vanhoef had exposed a "serious" vulnerability in the WPA/WPA2 encryption protocol, which most mobile devices and routers use to encrypt Wi-Fi traffic.

Chinese news website Qianlong later said further research had shown the vulnerability — called Key Reinstallation Attacks, or KRACK — was not a major problem as it required a hacker to be within a certain range of his or her target.

On Wednesday, the Beijing city government issued a statement that urged the public to update the firmware on terminal devices and routers, but said there was no need to change Wi-Fi passwords.

The statement also warned of the risk of entering your online payment password while connected to public Wi-Fi.