Japan's first robot bartender has begun serving up drinks in a Tokyo pub in a test that could usher in a wave of automation in restaurants and shops struggling to hire staff in an aging society.

The repurposed industrial robot serves drinks in its own corner of a pub run by restaurant chain Yoronotaki. A face on an attached tablet computer smiles as it chats about the weather while preparing orders.

The robot, made by QBIT Robotics, can pour a beer in 40 seconds and mix a cocktail in a minute. It uses four cameras to monitor customers to analyze their expressions with artificial intelligence software.