SHANGHAI (REUTERS) - China's economic growth will likely slow to 6.9 per cent this year amid gloomy short-term macroeconomic trends and the threat of deflation, state media quoted an annual report from a top government think tank as saying.

The Chinese Academy of Social Sciences (CASS) said in its "blue book" report on China's economy that the slowdown was wrought by falling investment by companies and individuals, and growing debt pressures faced by local governments, the Shanghai Securities News reported.

The National Bureau of Statistics earlier this month revised China's 2014 economic growth to 7.3 per cent, down from a previous reading of 7.4 per cent which was its slowest rate in 24 years. The economy expanded 7 per cent in the second-quarter.

Beijing has only said that it is targeting growth this year of around 7 per cent. CASS's status as a premier state-backed centre for academic and policy research means its outlook to a certain extent reflects central government thinking.

The report, published on Monday, said the economy was intimately linked with a demographic window - defined as a period when a country's working-age population reaches its height - that had opened in China in previous years.

It estimated that the country's labour force would contract 0.4 per cent over 2016-2020, having grown 0.61 per cent over 2008-2015 and 1.58 percent over 1985-2007.

CASS also said that the country's financial markets development and transformation needed more time.

The report urged the reining in of overspending, "lazy" regional governments, diversifying sources of fiscal revenue, implementing tax cuts if local governments were taking too long to spend their budgets, and to make reforms to the fiscal spending structure.