The banking industry of China is getting into full swing, but not without worries from investors and experts.

In the first three quarters this year, the country's 16 listed commercial banks raked in combined net profits of 529.3 billion yuan ($79 billion), surging 34 percent from a year ago. Of this, around 74 percent went to the "big four" lenders—the Industrial and Commercial Bank of China (ICBC), China Construction Bank, Bank of China and Agricultural Bank of China (ABC).

ICBC retained its position as the world's most profitable bank by generating 127.8 billion yuan ($19.1 billion) in net profits in the January-September period, soaring 27.2 percent year on year. ABC, the last of the "big four" to go public, earned 70.2 billion yuan ($10.5 billion) in the first three quarters, a growth of 36.3 percent from one year earlier.

Total domestic assets of Chinese banks increased 20.4 percent year on year to 90.6 trillion yuan ($13.1 trillion) by the end of September, said the China Banking Regulatory Commission.

The growth was largely driven by expanding interest income as their net interest margins widened, said Huang Can, a senior analyst at the China Cheng Xin International Credit Rating Co. Ltd (CCXI).

A cause for concern is the slight slowdown in intermediary businesses as regulations are tightened, he said.

Short-term risks facing the banking industry remain subdued because the government stepped up its handle over housing mortgages and the financing vehicles of local governments, said a report by the CCXI.

But longer-term challenges remain as non-performing loans might rebound in the future, the report said.