China's financial system is "almost certain" to face a full blown banking crisis according to a senior international economist.

Gabriel Stein, of economic consulting firm Oxford Economics, told a Sydney audience on Tuesday that Chinese authorities were understating the extent of bad loans on their banks' books and faced tough choices in dealing with the potential bank failure.

Even the failure of a small bank could trigger a crisis of confidence in the Chinese financial system, says economist Gabriel Stein. Credit:Reuters

"We don't know when there will be a China banking crisis and how it will play out but it is almost certain there will be one," said Mr Stein, a professor at the University of London who served as chief economist at consulting firm Lombard Street from 1991 to 2012.