A passenger scans QR code to buy ticket at a station of subway Line 9 in Shenzhen, south China, Nov. 20, 2017. (Xinhua/Mao Siqian)

SHENZHEN, July 14 (Xinhua) -- More than half of passengers in Shenzhen are using phones and scanning to enter the subway as the total number of QR code payment users exceeds 20 million, tech firm Tencent said Sunday.

Statistics released by the company has shown that 54 percent of the 20 million users are under the age of 30.

Code scanning has become the preferred payment method for tourists visiting the city, who account for 45 percent of the total number of users.

The subway QR code is a "take-and-pay"-style mini program developed by Tencent on its WeChat platform.

So far, the mini program has been activated in seven cities in the Guangdong-Hong Kong-Macao Greater Bay Area, with full coverage in the metro networks of Shenzhen and Guangzhou.