* HSI flat, H-shares -0.1 pct, CSI300 +0.3 pct
* Auto firms rise on H1 sales, policy support for green cars
* Chinese property developers strong on hopes of more easing (Updates to midday)
By Grace Li
HONG KONG, July 11 (Reuters) - China shares edged up early Friday, aided by gains for auto stocks on improved first-half car sales and belief that a government policy promoting "green" vehicles will help in the second half.
Hong Kong markets opened lower, following losses overnight on U.S. bourses, then scratched out gains that couldn't be maintained as banks underperformed.
At midday, the Hang Seng Index was flat at 23,230.63 points. The China Enterprises Index of the top Chinese listings in Hong Kong inched down 0.1 percent. For the week, they were down 1.3 and 1.2 percent, respectively.
The CSI300 of the leading Shanghai and Shenzhen A-share listings was up 0.3 percent, while the Shanghai Composite Index rose 0.4 percent at 2,045.40 points.
They were down 1.4 and 0.7 percent this week, respectively, and could have their first weekly loss in three. Both mainland indexes have moved in a 100-point range since May.
Zhang Yanbin, an analyst at Zheshang Securities in Shanghai, said investors are unwilling to go short in the current market environment.
He said recent moves, including encouragement from regulators for insurance funds to go into shares, should be "positive hints" for markets.
Among the top CSI300 boosts, SAIC Motor Corp added 1.9 percent, while Chongqing Changan Automobile climbed 3.2 percent to a record high.
During the first half, vehicle sales rose 8.4 percent, according to the China Association of Automobile Manufacturers.
On Wednesday, China's cabinet said the country will stop levying sales tax on approved models of green cars from Sept. 1 through to the end of 2017, in a bid to tackle pollution.
Chinese property developers again posted solid gains, with Poly Real Estate adding 3.1 percent and China Vanke 2.2 percent.
On Thursday, Jinan in eastern Shandong province removed restrictions on home purchases. The official China Securities Journal said in a report on Friday it expected 30 cities to ease rules on house-buying this year.
Feitian Technologies, among the first three new mainland listings after a four-month hiatus, jumped by its daily limit for the 12th time on Friday. It was at 136.13 yuan.
$1 = 6.2074 Chinese Yuan Editing by Richard Borsuk