Before the market opened, Li said in comments posted on a government website that China had the confidence and ability to deal with challenges faced by its economy, but had nothing to say on the three-week plunge that has knocked around 30 percent off Chinese shares since mid-June.

After a brief pause in the slide on Monday, the CSI300 index <.CSI300> of the largest listed companies in Shanghai and Shenzhen ended down 1.8 percent on Tuesday, while the Shanghai Composite Index <.SSEC> lost 1.3 percent. [.SS]

The ChiNext growth board <.CHINEXTC>, home to some of China's giddiest small-cap valuations, fell 5.1 percent.

Qi Yifeng, analyst at consultancy CEBM, said government measures were not strong enough to reverse the downtrend, especially as it was a liquidity issue for many who had borrowed to buy shares and were now forced to sell to meet margin calls.

"It's just a matter of whether it will fall more slowly, or continue to slump in freefall," he said.

Global investors have grown increasingly concerned about China's volatile stock markets, fearing a full-blown crash could destabilise the world's second-biggest economy.

Commodities markets are also taking fright at what the slump says about the underlying economy, with prices of copper , coal , natural gas and iron ore <.IO62-CNI=SI> falling back towards their 2015 lows.

ORCHESTRATED CAMPAIGN

In an attempt to arrest the sell-off, China has arranged a curb on new share issues and orchestrated brokerages and fund managers to promise to buy at least 120 billion yuan ($19 billion) of stocks, helped by China's state-backed margin finance company, which in turn has a direct line of liquidity from the central bank.

The official Shanghai Securities News reported on Tuesday that China's major insurance firms ploughed tens of billions of yuan into blue-chip exchange-traded funds (ETF) and large caps on Monday.

China Life Insurance Co Ltd (>> China Life Insurance Company Limited) bought a net 10 billion yuan in index funds, while China Pacific Insurance Group (>> China Pacific Insurance (Group) Co., Ltd) and other insurers each invested more than 1 billion yuan, the newspaper said.

That helped the indexes rise just over 2 percent on Monday, but the relief was shortlived.

Unlike other major stock markets, which are dominated by professional money managers, retail investors account for around 85 percent of trading in China, which contributes to the volatility of Chinese equities.

"Where is the promised 120 billion yuan?" asked one retail investor from Hangzhou, who gave his surname as Liu. "It's all going to blue chips. Don't they know that retail investors are all trapped in the small caps? My stocks opened up 10 percent but closed down the (10 percent) limit!"

Blue chips fared best as a result of the targeted buying, especially the big five banks; Industrial and Commercial Bank of China (>> Industrial and Coml Bank of China Ltd), China Construction Bank (>> China Construction Bank Corporation), Bank of China (>> Bank of China Limited), Agricultural Bank of China (>> Agricultural Bank of China Ltd) and Bank of Communications (>> Bank of Communications Co Ltd) were all up almost by the 10 percent limit.

DUCKING OUT

Traders are increasingly nervous about the unusually large number of Chinese companies asking for their shares to be suspended from trading, fearing that many of them are looking for excuses to duck out of the market turmoil.

About a quarter of the roughly 2,800 companies listed in Shanghai and Shenzhen had filed for a trading halt by the close on Monday, and on Tuesday the Securities Times said another 200 had announced a suspension.

Investors were also reacting to news of tightened restrictions on futures trading on a major small-cap index.

The rapid decline of China's previously booming stock market, which had more than doubled in the year to mid-June, is a major headache for President Xi Jinping and China's top leaders, who are already struggling to avert a sharper economic slowdown.

Beijing's interventionist response has also raised questions about its ability to enact the market liberalisation steps that are a centrepiece of its economic reform agenda.

A surprise interest-rate cut by the central bank at the end of June, relaxations in margin trading and other "stability measures" did little to calm investors.

Underlining scepticism beyond mainland China about the sustainability of the new measures, Hong Kong listed shares of Chinese brokerages plunged on Monday.

In addition, 28 companies that had been approved to launch IPOs announced they had suspended their plans.

Lei Mao, assistant professor of finance at Warwick Business School, said government measures to support the market distorted the allocation of funds and trading behaviour and could create the conditions for further sharp falls.

"Even an optimistic investor should not participate in the market for now," he said.

(Additional reporting by Shanghai newsroom; Writing by Will Waterman; Editing by Alex Richardson)

By Samuel Shen and Pete Sweeney