* CSI300 +0.1 pct; SSEC +0.1 pct; HSI -0.6 pct
* Lower Sept inflation rate points to deflationary pressure
* Environment stocks rise ahead of China five-year plan
SHANGHAI, Oct 14 (Reuters) - China stocks ended Wednesday morning roughly flat, as cooling September inflation data reinforced expectations that Beijing will have to roll out more stimulus measures.
Both the CSI300 index and the Shanghai Composite Index were up 0.1 percent by lunch time, to 3,447.48 points and 3,295.20 points respectively.
Hong Kong stocks fell as a week-long rebound appeared to have lost momentum.
China's consumer price index (CPI) rose 1.6 percent in September from a year earlier, lower than expected, while producer prices extended their slide to a 43rd straight month.
Gerry Alfonso, director of Shenwen Hongyuan Securities, said the low CPI figure, together with Tuesday's foreign trade data, suggest deflationary pressures but the overall economic situation seems to be normalizing.
Low inflation raises the hopes of further monetary easing, with brokerage Guotai Junan Securities Co saying on Wednesday that China still has big room to cut interest rates.
Reflecting rising risk appetites among mainland investors, outstanding margin lending in China has expanded for the past four sessions.
On Wednesday, main sectors had mixed performance, with banking and property shares sagging while energy and commodity-related stocks rose.
In Hong Kong, the Hang Seng index dropped 0.6 percent, to 22,470.84 points, and the Hong Kong China Enterprises Index lost 0.5 percent, to 10,390.56.
Shares of Chinese environment-related companies rose both in the mainland and Hong Kong, on hopes that China's new five-year plan, expected to be unveiled this month, will include incentives to invest in the sector. (Reporting by Samuel Shen and Pete Sweeney; Editing by Richard Borsuk)