* CSI300 +0.4 pct; SSEC +0.7 pct; HSI -0.9 pct
* Market helped by news on further restrictions on share sales
* Dec activity in China's services sector remains weak
SHANGHAI, Jan 6 (Reuters) - China stocks edged up on Wednesday on hopes that regulators would extend a ban on share sales by major stakeholders as Beijing scrambled to avert a potential repeat of last summer's market crash.
State media reported the ban on such share sales, which had been due to expire on Friday, will remain in place until new rules to manage the process are promulgated.
The market was also helped by statements from at least 30 companies saying their controlling shareholders or senior executives would not sell shares on the secondary market within the next six or 12 months to help stabilise the stock market.
The reports were the latest damage-control measures announced after China's major benchmark indexes plunged 7 percent on Monday, forcing the first-ever nationwide trading halt and roiling global markets.
The blue-chip CSI300 index rose 0.4 percent to 3,490.95 points by the lunch break on Wednesday, while the Shanghai Composite Index gained 0.7 percent to 3,310.24.
Many traders largely attributed Monday's sell-off to fears that the expiry of the share sale ban, imposed during the height of the market rout last year, could see an estimated 1.24 trillion yuan ($190.23 billion) of shares dumped onto the market.
However, some traders say further restricting share sales by major shareholders was not justified, and would do little to help the market.
"Extending the restrictions would only prolong the problem, rather than cure it," said Shen Weizheng, fund manager at Shanghai-based Ivy Capital.
Companies can extend the ban for six months, "but what about six months later? It's like the sword of the Damocles overshadowing the market."
He noted that the fundamental elements that have been dragging the markets lower are the prospects of prolonged weakness in the economy and more capital outflows, rather than expiration of the share sales ban.
Activity in China's services sector expanded at its slowest rate in 17 months in December, a private survey showed on Wednesday, in a further indication that the world's second-largest economy may be losing steam.
Many sectors rebounded on Wednesday, though, with resources and energy sectors leading gains, up over 3 percent.
In Hong Kong, the Hang Seng index dropped 0.9 percent to 20,994.31 points, while the Hong Kong China Enterprises Index lost 1.1 percent to 9,123.39.
Hong Kong's private sector activity deteriorated again in December for the 10th month running, with the rate of contraction the steepest since September.
Reporting by Samuel Shen and Pete Sweeney; Editing by Kim Coghill