May 18 (Reuters) - Average new home prices in China's 70 major cities fell for the eighth consecutive month in April from a year earlier, down 6.1 percent.

New home prices in Beijing fell 3.2 percent last month from a year earlier, versus the previous month's drop of 3.7 percent, the National Bureau of Statistics said on Monday.

They rose 0.7 percent in April from March.

Shanghai's home prices were down 4.7 percent last month from a year ago, versus a 5 percent fall in March. They were up 0.6 from the previous month.

China's real estate investment growth continued to slow in the first four months of 2015 to the lowest since May 2009 as new construction weakened, and economists expect it to improve only after excess housing inventory is slowly worked off.

The weak property market is seen as one of the major risks for the economy, which looks set for its worst year in 25 years this year.

(Reporting by Clare Jim; Editing by Kim Coghill)