* CSI300 +1.2pct; SSEC +1.3pct HSI -0.1pct
* Beijing steps up crackdown on short-selling
* China Commerce Ministry expects import growth to remain sluggish
HONG KONG, Aug 4 (Reuters) - China stocks rose just over one percent on Tuesday morning after Chinese authorities announced new measures to crack down on short selling, which has been partly blamed for the plunge in mainland equities last month.
Both the Shenzhen and Shanghai stock exchanges unveiled measures that would make it more difficult for speculators to profit from hourly gyrations in stock prices.
Beijing has taken a raft of steps to support Chinese share markets after they lost more than 30 percent of their value since peaking in June.
The CSI300 index rose 1.2 percent, to 3,873.66 points at the end of the morning session, while the Shanghai Composite Index gained 1.3 percent, to 3,671.49 points.
China CSI300 stock index futures for August rose 4.5 percent, to 3,783.6, 90.06 points below the current value of the underlying index.
"The market is still very volatile ... investors are likely to be quiet and see what the next step of the government will be," said Patrick Yiu, a director of CASH Asset Management in Hong Kong.
"The overall market momentum is not likely to pick up anytime soon and the economy in China is still very weak," added Yiu.
China's Commerce Ministry said import growth is likely to remain at a low level on Tuesday, just a day after data from a private survey showed China's factory activity shrank more than initially estimated in July.
The Hang Seng index dropped 0.1 percent, to 24,378.83 points.
The Hong Kong China Enterprises Index gained 0.2 percent, to 11,029.47.
The index measuring price differences between dual-listed companies in Shanghai and Hong Kong stood at 138.73.
A value above 100 indicates Shanghai shares are pricing at a premium to shares in the same company trading in Hong Kong, and vice versa.
The northbound quota for the Hong Kong-Shanghai Stock Connect, currently set at 13 billion yuan, saw net outflows of 0.20 billion yuan.
Total volume of A shares traded in Shanghai was 16.60 billion shares, while Shenzhen volume was 12.42 billion shares.
Total trading volume of companies included in the HSI index was 0.5 billion shares.
China stock market graphics suite reut.rs/1HcUe19
(includes timeline of crash, PE ratios, market caps)
A-share account openings spike bit.ly/1wvJ9S9
Comparison of stock indexes and selected company stocks
Chinese A-shares vs developed and emerging stocks
link.reuters.com/rac25w0.2 (Reporting by James Pomfret and Donny Kwok; Editing by Simon Cameron-Moore)