* HSI +1.1 pct, H-shares +1.7 pct, CSI300 flat
* H-shares of China banks rise on cenbank injection report
* Macau casinos sink further as Sept revenue expected to decline (Updates to midday)
By Grace Li
HONG KONG, Sept 17 (Reuters) - Hong Kong shares rebounded from eight-week lows on Wednesday, tracking gains in U.S. markets on speculation the Federal Reserve will maintain a pledge to keep rates low when a two-day policy meeting ends later in the day.
China shares remained weak after a choppy morning session, however, despite a media report saying its central bank was injecting liquidity into the country's top lenders.
By midday, the CSI300 of the leading Shanghai and Shenzhen A-share listings was flat, while the Shanghai Composite Index slipped 0.2 percent to 2,292.41 points.
Both indexes posted their biggest daily loss in more than six months on Tuesday, with Shanghai volume more than double its 20-day moving average.
The Hang Seng Index, which had fallen eight days in a row, climbed 1.1 percent to 24,395.07 points. The China Enterprises Index of the top Chinese listings in Hong Kong rose 1.7 percent.
"If that is the case for the Federal Reserve to have a clear announcement about timing of the interest rate hike, it would help ease uncertainty in the market," said Castor Pang, head of research at Core Pacific-Yamaichi in Hong Kong.
The Dow hit a record intraday high after the Wall Street Journal's Fed watcher Jon Hilsenrath said the central bank would keep the words "considerable time" in its policy statement, though it might qualify them.
Hong Kong-listings of China's top five banks outperformed after the Wall Street Journal, citing an unnamed Chinese bank executive, reported that the People's Bank of China was pumping 100 billion yuan ($16.28 billion) into each of them.
Industrial and Commercial Bank of China added 1.8 percent, while Bank of Communications leapt 3.2 percent. China Construction Bank, Bank of China and Agricultural Bank of China all rose 1.4 percent.
The report, however, failed to help mainland shares and lift sentiment in the onshore market.
"The overall market demand for borrowing seems to be very weak... so the injection is not the major concern for investors," said Pang.
The Macau gambling sector was hard hit again after two days of heavy losses. SJM Holdings and MGM China each slumped more than 5 percent.
In a research note on Tuesday, Barclays said it expected a 16.2 percent decrease in gross gaming revenue for September and that weak trends could continue for the rest of the year.
$1 = 6.1430 Chinese yuan Editing by Jacqueline Wong