HONG KONG: Hong Kong's main stock index dived 8 percent on Thursday as a sell-off in mainland Chinese shares accelerated despite new measures to support the market.

Other markets in Asia were also sharply down as investor sentiment was hit by the twin worries of the China rout and Greece's uncertain future in the euro.

The Shanghai Composite Index ended nearly 6 percent lower at 3,507.19. The market turmoil in mainland China spilled over into Hong Kong, pushing down the benchmark Hang Seng Index nearly 2,000 points, or about 8 percent, to 23,019.85 about half an hour before the close of trading.

Japan's Nikkei 225 fell 3.1 percent to 19,737.64 and South Korea's Kospi lost 1.2 percent to 2,106.21.

A slew of official measures to provide support to Chinese stock markets have failed to stop the selling.

The Shanghai benchmark is down more than 30 percent since peaking June 12 after a sizzling yearlong rally.

Millions of novice investors piled into the market when it was at its most frothy. Some made big profits but the slump has left many with shares worth less than they paid and hoping for a rebound so they can sell.