* Jan-May property investment growth slowed to 14.7 pct y/y
* Jan-May property sales revenues down 8.5 pct y/y
* Property downturn is expected to continue -analysts (Adds details, comments)
BEIJING, June 13 (Reuters) - Growth in real estate investment in China slowed in the first five months of 2014, while property sales and new construction fell, adding to signs of cooling in the property market that has become a persistent drag on the broader economy.
The sluggish performance in real estate comes as the world's second-largest economy faces its weakest pace of growth in 24 years this year.
Real estate investment, which affects more than 40 other sectors from cement to furniture, rose 14.7 percent in the January to May period from the same period a year ago, down from an annual rise of 16.4 percent in the first four months, official data showed.
Newly started property construction fell 18.6 percent in the first five months from a year earlier, the fourth consecutive period of decline.
Analysts predicted the worst is yet to come.
"The trend of slowing property investment growth is likely to continue in coming months as more and more home buyers stay the sidelines," said Tang Jianwei, an economist at Bank of Communications in Shanghai.
Property sales dropped 7.8 percent in the January-May period from a year earlier in terms of floor space and fell 8.5 percent in terms of value, the National Bureau of Statistics also said in a statement on its website, www.stats.gov.cn.
That compared with annual drops of 6.9 percent and 7.8 percent, respectively, in the first four months.
As the sector accounts for more than 15 percent of China's annual economic output, a prolonged cooling of property market will likely influence whether the economy suffers a shallow or deep downturn.
"The biggest uncertainty in the economy this year is the property sector," said Tang.
After a strong performance in 2013, China's real estate market has softened. Sales have slowed and banks have become increasingly cautious about lending to developers and home-buyers.
NBS data showed China had 352.8 million square metres of unsold homes at the end of May, over three times last year's average monthly sales.
"We think tighter financing conditions in the second half of 2013, overbuilding and increased developer leverage have worsened the housing market's supply and demand picture," Jian Chang, economist at Barclays, wrote in a note to clients.
"We expect the property downturn to continue into 2015."
A private survey conducted by China's Southwestern University of Finance and Economics showed 22.4 percent of China's urban homes were vacant in 2013, up 1.8 percentage points from 2011.
China's official media, however, has played down the sharp correction risks of property market and claimed there is no accurate data available for home vacancy rates.
Feng Jun, chief economist at the Ministry of Housing and Urban-Rural Development, said last week that current slowdown in China's property market is a normal adjustment after past stellar performance.
Because of China's relatively low household leverage, the risk of defaulting is limited. Chinese home buyers put down at least 30 percent of the purchase price, with second home buyers paying at least 60 percent, while some pay entirely in cash.
The government have made efforts to support the flagging industry. The central bank last month asked banks to quicken mortgage lending to home buyers and some local governments have relaxed home purchases rules to encourage home buying.
(Reporting By Xiaoyi Shao and Koh Gui Qing; Editing by Kim Coghill)