BEIJING

A raft of government-led emergency measures aimed at arresting China's nose-diving sharemarkets has fallen embarrassingly short, with sustained selling on Monday wiping out most gains from the benchmark Shanghai index's best start to a trading session since 2008.

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The result has left analysts questioning both the ability and rationale of the government and financial regulators to stem losses that have stretched to more than $US3 trillion in the past three weeks, and the extent to which a continued free-fall in the market will impact the broader economy.

"Clearly the reaction from the market was nowhere near what was hoped for," said Fraser Howie, managing director of Newedge Singapore and an expert on China's capital markets.