China's vacant commodity building area surged 17.8 percent year on year by the end of May this year, and more than 60 percent of the buildings had remained unsold for over one year, according to a report of the National Development and Reform Commission.

The vacant commodity buildings, including office buildings and residential buildings, totaled 121.55 million square meters in floor space. Of the total, 65.6 percent or 79.79 million square meters, had been waiting for buyers for more than one year, said the report released on Friday.

Residential buildings that remained vacant increased by 13.4 percent to 67.28 million square meters in floor space in the same period.

Analysts attributed the increasing vacant housing mainly to the short supply of affordable housing for lower income earners and the rising housing prices, which grew by 5.5 percent in the first quarter this year.

A survey in 70 big and medium-sized Chinese cities, conducted by the National Statistics Bureau, showed that the price of newly-built commodity housing as a whole rose by 6.9 percent, 6.2 percent and 5.9 percent in January, February and March this year, though the growth slowed down month by month.