The rate of "subprime" motor loans overdue by more than 60 days rose to 5.16 per cent in February. This surpassed the post-financial crisis peak and was the highest since the 5.96 per cent reading in October 1996, according to the rating agency.

Subprime car loans have long been a concern for analysts, some of whom feared that rapid issuance since the crisis and weakening lending standards would cause problems in the market for securitised motor loans. There, banks repackage loans into asset-backed securities and sell them on to investors, much like they did with subprime mortgages in the 2000s.

"Sharp origination growth, increased competition and weaker underwriting standards over the past three years have all contributed to the weaker performance of the past year," Fitch Ratings said in its report.