China's central bank said Thursday it will continue to support liquidity need of China Securities Finance Corporation Limited (CSF), the national margin trading service provider, to stabilize a tumbling stock market.

The People's Bank of China (PBOC) said it has made sufficient re-lending to the CSF and approved the latter to issue short-term financial bonds in the interbank market to replenish liquidity.

The CSF is the only institution to provide margin financing loans to securities companies. It has offered 260 billion yuan (42 billion U.S. dollars) of stock-secured credit for 21 brokerage firms to conduct self-run share purchasing on the market.

The PBOC is trying to guide more capital into the market to rein in a continued plunge and restore investors' confidence as Chinese shares have been in a downward spiral since hitting a peak in June. The benchmark Shanghai Composite Index has shed more than 30 percent.