UPDATE 1-China regulator says banks have passed the 'most difficult' period

* Banks still face huge pressure - CBRC official

* China's largest listed banks producing better results

* CBRC says fall in non-performing loans a long-term trend (Adds quotes and background)

BEIJING, Nov 16 (Reuters) - Chinese banks have passed their "most difficult" period, though they still face huge pressure, a senior official of China's banking regulator said on Thursday.

The view comes as China's largest banks have started reporting better earnings this year, after successive quarters of rising non-performing loans and narrowing margins.

The improved results follow Beijing's introduction of a series of measures to help struggling borrowers, such as debt-for-equity swaps.

But while there's been better performance by the country's largest four listed state-owned lenders, their smaller counterparts continue to report tepid results.

Yu Xuejin, chairman of the supervision panel for important state-owned financial institutions at the China Banking Regulatory Commission (CBRC), said a decline in non-performing loans "is not a short-term thing, but is a trend."

"The most difficult period for banks is over," he told a finance forum in Beijing.

Banks' balance sheets will continue to expand in the long run, said Yu.

The regulator also said banks need to deal with a raft of new measures aimed at controlling risk and leverage in the financial system, with everything from lending practices to shadow banking under the microscope. (Reporting by Shu Zhang and Ryan Woo; Writing by Engen Tham; Editing by Richard Borsuk)