SHANGHAI, Aug 17 (Reuters) - China and Hong Kong stocks climbed on Wednesday, led by gains in developers on rising hopes that the Chinese government would roll out supportive measures to prop up the country's ailing property sector.

** By the midday break, the benchmark Shanghai Composite index had climbed 0.3%, while the blue-chip CSI 300 index was up 0.7%.

** In Hong Kong, the benchmark Hang Seng Index advanced 0.8%, while the Chinese H-shares listed in Hong Kong also gained 0.8%.

** The property sector was among the top gainers after sources told Reuters that China would guarantee new onshore bond issues by a few select private developers to support its embattled property sector, while the state planner said it would boost economic demand and speed up infrastructure projects.

** The CSI real estate index had jumped 2.93% by noon, while Chinese developers listed in Hong Kong were up 0.98%. However, some analysts and economists said the gains might be temporary as the policy support was far from enough.

** "The policy response to the deteriorating property sector may be too slow and uncoordinated in the lead-up to the once-in-a-decade political reshuffle," said Lu Ting, chief China economist at Nomura.

** "The credit support Chinese regulators plan to provide to select developers could be of some help, though it's far from a comprehensive solution to the big woes in the property sector."

** Separately, Premier Li Keqiang pledged that China would step up macro-economic policy support for the economy, after a slew of key economic gauges including credit lending data and activity indicators showed growth unexpectedly slowed last month.

** Li made the comment during a video meeting with senior officials from six major provinces - Guangdong, Jiangsu, Zhejiang, Shandong, Henan and Sichuan.

** "In our view, the meeting highlighted the urgency to fuel the recovery momentum but the focus remained on the implementation of existing pro-growth measures, instead of introducing new growth initiatives," said Ken Cheung, chief Asian FX strategist at Mizuho Bank.

(Reporting by Shanghai Newsroom; Editing by Subhranshu Sahu)