BEIJING, July 8 -- China's central bank vowed support for securities companies to steady the stock market on Wednesday, as the country passes more measures to do the same.

It will support China Securities Finance Corporation Limited (CSF), the national margin trading service provider, in its efforts to get liquidity and steady the stock market.

The People's Bank of China will actively support the CSF to get liquidity through channels such as interbank lending, floating financial bonds and mortgage financing, it said in an online statement.

The CSF is the only institution to provide margin financing loans to qualified securities companies. It works to facilitate the margin transactions of securities companies in market operation methods and improve China's margin transactions system.

It was jointly founded by the Shanghai Stock Exchange, Shenzhen Stock Exchange and China Securities Depository and Clearing Corporation Limited in October 2011.

The central bank will monitor the stock market closely and continue to support the CSF through various channels to steady the stock market and safeguard the bottom line that no systematic and regional financial risks will occur, it said.

The central bank's announcement came amid the country's concerted efforts to stem the massive sell-off in the stock market.

The CSF will purchase more shares of small- and medium-sized listed companies to ease stock market liquidity, said the China Securities Regulatory Commission (CSRC), the country's securities watchdog.

China's insurance regulator eased rules for insurance companies to put money in the market. Qualified insurance companies will be allowed to invest up to 10 percent of their assets in a single blue chip, up from the previous 5 percent, said a notice from the China Insurance Regulatory Commission.

China Financial Futures Exchange said it will raise the margin requirements for sell orders on CSI 500 index futures to curb speculation. Traders must pay margin requirements equivalent to 20 percent of the contract value starting from Wednesday's clearing, up from the previous 10 percent.

China's stock market has been in a downward spiral since hitting a peak in June, with the benchmark Shanghai Composite Index shedding more than 30 percent.

The government has rolled out a streak of supportive measures, including asking 21 major securities brokers to spend 128 billion yuan (20.61 billion U.S. dollars) on exchange traded funds (ETF) which track the performance of blue chip stocks on Monday.