BEIJING, July 15 (Reuters) - China's property investment fell 5.4% from a year earlier in the first half of the year, after a 4.0% decline in the first five months, official data showed on Friday.

Property sales by floor area slumped 22.2% year-on-year in January-June, compared with a 23.6% fall in January-May, according to data from the National Bureau of Statistics (NBS).

New construction starts measured by floor area fell 34.4% in the first six months from a year earlier, after a 30.6% plunge in the first five months of the year.

Funds raised by China's property developers declined 25.3% year-on-year in January-June, after a 25.8% drop in January-May.

China's real estate sector, which broadly contributes one-third of gross domestic product (GDP), is in crisis as a string of developers default on their debts and a growing number of homebuyers refuse to pay mortgages on stalled projects. (Reporting by Liangping Gao and Kevin Yao; Editing by Jacqueline Wong)