China's main stock index hit a fresh all-time high after breaking a key barrier of 4,000 points due to the soaring blue chip stocks as investors shrugged off official warnings of a possible market bubble amid soaring corporate profits.

The benchmark Shanghai Composite Index, the most widely watched indicator of the mainland's stock market, gained 1.60 percent to end at 4,013.08 points, breaching the psychologically important mark of 4,000 for the first time.

That marks a gain of 50 percent so far this year on top of a 130 percent rally in 2006.

Blue chip stocks showed strong performances. China Unicom, the nation's second largest wireless operator, jumped its daily limit of 10 percent to close at 6.35 yuan per share.