The International Monetary Fund on Thursday warned of brewing risks in China's banking system as it found dozens of crucial lenders needed to beef up their defences against possible financial crises.

The IMF report comes a day after regulators in Beijing drafted new rules to strengthen bank funding, and follows a number of alerts about a ballooning debt problem in the world's number-two economy.

Near the top of the list in the IMF study on the stability of China's financial system is the need for banks to increase their capital to ward off risks from mounting debt.

China has largely relied on debt-fuelled investment and exports to drive its tremendous economic growth, but the Fund said this model has reached its limits.