Beijing: Nine million people have been banned from buying plane tickets and another 3 million from buying business-class train tickets, under a pervasive social scoring system being built by the Chinese government.

The type of bad behaviour that can lead to being blacklisted from travel ranges from a shopkeeper in Qingdao leaving four electric bikes parked on a footpath that obstructed pedestrians, to illegal home renovations by a property owner who refused to pull down his new sun room.

Many people have been blocked from using planes and trains for unpaid fines, with more than 815,000 court debtors placed on the blacklist.

A shopkeeper was blacklisted for leaving bicycles on the footpath, blocking pedestrian traffic. Credit:AP

Zhang Yong, deputy director of the National Development and Reform Commission, which is overseeing the social credit system, on Tuesday conceded there were problems with it, telling reporters that "quite often" someone placed on the blacklist is unable to travel even after the debt was repaid.