Fitch Ratings warned on Tuesday that the growing shadow banking sector in China, if not dealt with properly, could puncture the country's credit bubble and spark a financial crisis.

In a speech in Hong Kong, Charlene Chu, senior director of financial institutions at the global ratings agency, said that at the end of 2012 Chinese lenders were involved, directly or indirectly in three-quarters of the 11.7 trillion yuan ($1.91 trillion) of outstanding credit "in the shadows" or extended by non-bank financial institutions.

Little light is shed on the quality of those issuers or borrowers in the shadow credit sector, which accounts for a third of the country total 34 trillion yuan of non-loan credit.