* August annual new home prices expand 8.8% vs 9.7% in July
* Month-on-month new home prices grow 0.5% vs 0.6% in July
* 55 out of 70 cities reported higher prices vs 60 in July (Adds more quotes, details on price trends by city-tier)
By Yawen Chen and Ryan Woo
BEIJING, Sept 17 (Reuters) - China's new home prices grew at their weakest pace in nearly a year in August as a cooling economy and existing curbs on speculative buying put a dent on overall demand.
Wary of property bubbles, Chinese regulators have vowed to refrain from stimulating the real estate sector as they roll out measures to boost the broader economy hit by the Sino-U.S. trade war and slowing consumer demand.
Average new home prices in China's 70 major cities rose 8.8% in August from a year earlier, compared with a 9.7% gain in July and the weakest pace since October 2018, Reuters calculated from official National Bureau of Statistics (NBS) data on Tuesday.
On a monthly basis, average new home prices rose 0.5% in August, less than July's growth of 0.6% and the smallest increase since February. However, it still marked the 52nd straight month of gains.
Most of the 70 cities surveyed by the NBS still reported monthly price increases for new homes, though the number was down to 55 from 60 in July.
The property sector has held up as one of the few bright spots in the world's second-largest economy.
China's property investment grew at its fastest pace in four months in August, data showed on Monday, in contrast to a protracted slowdown in industrial output and investment.
But some analysts said the rebound in investment was likely due to developers rushing to meet government requirements before they can start sales on growing financing pressure and worries about the market's prospects as regulators have made clear that supervision is only set to tighten.
Yang Yewei, a Beijing-based analyst at Southwest Securities, noted some developers have opted to cut prices, although the government's tight control over new launches suggests they may not tolerate large discounts.
A resilient real estate market has provided some cushion for the world's second-largest economy as policymakers try to revive the ailing manufacturing sector and restore flagging consumer confidence amid an escalating trade war with the United States.
But regulators are walking a tightrope, as rapidly-growing household debt and ever-rising home prices have also deepened fears about a sudden market correction and concerns over housing affordability.
In a sign the government has turned more hawkish on its housing policy as it manoeuvres to pump more credit into other areas of the economy, top Chinese leaders said in July they will not resort to using the housing market as a form of short-term stimulus.