BEIJING - When crowds of Chinese farmers leave their land and settled down in cities, the crop-growing master-hands may not have enough food to eat, an agricultural official warned Saturday.

Chen Xiwen, deputy director of the Leading Group on Rural Work under the Central Committee of Communist Party of China, said consecutive harvests China enjoyed over the past nine years are still insufficient to meet the growing demand for grain during rapid urbanization.

China's urbanization rate had reached 52.57 percent as of the end of 2012, 1.3 percentage points higher than the previous year, Chen said at the Annual Meeting of China's Economy 2012-2013 in Beijing.

The country must attach great importance to grain supply as urbanization may unleash new comers' demand for more farm produces amid income rises in cities, Chen said.

Some 21 million farmers became urbanites last year, and their diet structure is likely to change accordingly, as people living in cities generally consume more meat, eggs and vegetables, Chen said.

Although China produced 159 million more tonnes of grain last year than in 2003, imports figures have told the story of strained domestic grain supply. China's grain imports hit a record high in 2012 to stand at 72.3 million tonnes, according to Chen.

"If the country's grain output will not speed up, possible food shortage will threaten the development of urbanization," he warned.

In order to underpin the development of urban expansion, China has to make efforts to secure a stable supply of farm produces especially grain along with the urbanization ambition, Chen said.