BEIJING, Feb. 3 -- The purchasing managers' index (PMI) for China's non-manufacturing sector slipped for a third straight month in January due to a slowdown in the real estate sector, new data showed.

The index dropped to 53.4 percent last month, the lowest since February 2012, from 54.6 percent in December, according to official figures released on Monday.

The index tracks non-manufacturing sectors including construction, software, aviation, railway transport and real estate. A PMI reading above 50 percent indicates expansion, while a reading below 50 percent reflects contraction.

The monthly indicator is released by the National Bureau of Statistics (NBS) and the China Federation of Logistics and Purchasing (CFLP).

CFLP Vice Chairman Cai Jin attributed the drop mainly to a slowdown in the real estate sector in the past two months.

The price index for real estate dropped to below 50 percent from December to January, while that for the non-manufacturing sector as a whole dropped 1.9 percentage points to 50.1 percent.

Input prices saw the biggest decline of 2.4 percentage points compared to that the previous month.

"However, the sub-indices for retail business activities and new orders both rose for two consecutive months to above 60 percent as demand from residents increased before the traditional Spring Festival," Cai said.

The sub-index for the transportation and catering sectors also rose thanks to the festival, and that for prices charged by retail business rebounded to above 50 percent.

In January, the new export orders index rose 0.7 percentage point month on month to 50.1 percent, while the index for business outlook dropped 0.6 percentage point to 58.1 percent, indicating that fewer companies were optimistic about business prospects in the next three months, according to the NBS data.

PMI for the manufacturing sector dropped to a six-month low of 50.5 percent in January, according to official data released on Saturday.

Major PMI indices all declined in January, suggesting downward pressure on the economy, but in general, the country is still expecting stable growth, said Zhang Liqun, an analyst with the Development Research Center of the State Council.

China's economy expanded 7.7 percent in 2013, overshooting the official target of 7.5 percent, with pleasant changes spreading across the economy amid the country's rebalancing efforts.