Two grocery stores with unmanned checkouts completed a one-day trial in Beijing and the eastern city of Hangzhou on Saturday, testing the integrity of customers.

A QR code and guidance were placed in a cashier-free outlet belonging to the Vanguard supermarket chain downtown Hangzhou.

Customers assume the job of the cashier by scanning bar codes themselves. They were able to pay via mobile phone or put cash in an honesty box.

"It's very convenient. I think most people will accept this new way of purchase," a customer said.

The grocery store sold products worth 16,700 yuan (about $2,700) on Saturday but only received payment of 13,700 yuan from customers.

In Beijing's outlet under ampm, a convenience store chain, staff said some customers stole products or paid less. Currently, there are cashier-free stores in other parts of China including northeastern province of Jilin and eastern province of Shandong.

"Cashier-free supermarkets which reduce queuing time are developing fast abroad,," said Chen Liucheng, an Vanguard executive.

With an improved of credit system, he expects more cashier-free grocery stores to open in China.

The trial was jointly run by the two store chains and Sesame Credit, credit scoring service introduced by a financial affiliate of e-commerce giant Alibaba.