BEIJING, June 14 (Xinhua) -- China's fixed-asset investment (FAI) expanded 6.1 percent in the first five months, down from 7 percent for January-April.

On a monthly basis, the FAI went up 0.47 percent in May, according to data from the National Bureau of Statistics (NBS).

China has had a better investment structure and the economy is sound and steady, NBS spokesperson Mao Shengyong told a press conference Thursday.

Mao attributed the growth slowdown mainly to a deceleration in infrastructure investment, which went down to 9.4 percent in the first five months, 3 percentage points lower than the January-April level.

"Investment demand in the infrastructure sector has weakened from past levels after years of high investment growth have already brought substantial development to China's infrastructure construction," he said. "Meanwhile, as China moves to clean up irregular infrastructure projects amid government efforts to defuse financial risks, investment in the field has been affected."

Compared with softened infrastructure investment, private investment rose at a faster rate. FAI by the private sector climbed 8.1 percent year-on-year in January-May, up 1.3 percentage points from the growth in the same period last year.

Investment in manufacturing also grew 5.2 percent in the first five months, up from 4.8 percent for January-April. FAI to high-tech manufacturing and equipment manufacturing jumped 9.7 percent and 8.2 percent, respectively.

The pickup in manufacturing investment was backed by stronger consumption demand, an expansion in the manufacturing sector, higher industrial profits and government supporting policies to boost the real economy, according to Mao.

China's property development investment expanded 10.2 percent year-on-year in the first five months, slightly slower than the 10.3 percent in the January-April period.

Commercial housing sales measured by floor area rose 2.9 percent year-on-year, up 1.6 percentage points compared with the first four months.

Mao said further observation was needed to see the future trend of FAI as infrastructure investment was still under pressure, and expected the recovery in manufacturing investment to continue and real estate investment to maintain steady growth.

He said the government would work to further improve the management system and market environment, with a priority on supporting private enterprises and small- and medium-sized ones, so that the recovery in manufacturing would continue.