* CSI300 +0.4 pct; SSEC +0.3 pct; HSI +2.5 pct
* HSI heading toward biggest one-day gain in six weeks
* Sharp rebound in Hong Kong stocks could be short-lived-analyst
SHANGHAI, May 25 (Reuters) - China and Hong Kong tracked global markets higher on Wednesday, but analysts say the rebound is being driven by technical factors and remain wary of the near term amid the backdrop of a sluggish Chinese economy and a possible U.S. rate hike next month.
China's blue-chip CSI300 index rose 0.4 percent, to 3,074.30 points by lunch break, while the Shanghai Composite Index gained 0.3 percent, to 2,829.33 points.
Hong Kong stocks are heading toward their biggest one-day gain in six weeks, with the Hang Seng index jumping 2.5 percent while the Hong Kong China Enterprises Index surging 2.7 percent, to 8,526.75.
Alex Wong, Hong Kong-based director of Ample Finance Group, said HSI's rebound is technical in nature, and won't last long.
"The recent pattern in Hong Kong has been a sharp rebound following many sluggish sessions, but the index will then go lower gain," Wong said.
"If the U.S. raises rates again, that would certainly have a negative impact on Hong Kong stocks, and investors are fully aware of that."
Most sectors in Hong Kong rose, with energy and financial shares leading the charge.
Shares of Chinese sports brand Peak Sport Products Co Ltd soared 13 percent after saying its controlling shareholder plans to take the firm private.
But Belle International Holdings Ltd underperformed, up only 0.4 percent by midday, after saying its annual net profit fell 38 percent.
In China, sector performance varied. Banks and IT shares rose but transportation and property shares stocks fell.
Samuel Shen and Pete Sweeney; Editing by Shri Navaratnam