The department said rainfall in many parts of northern and central China had dropped by 50 to 80 per cent and the drought, which began in November, is said to have also affected 10.33 million hectares of crops.
Zhao Mifen, a farmer, told the Reuters news agency that "there was no snow, no rain".
Zhao and her husband, who farm one-fifth of a hectare in the flat plains near Xingtai, in southern Hebei province, said they had to supplement their income by making construction materials.
The state-run Xinhua news agency reported that almost half of the wheat crop in eight provinces - Hebei, Shanxi, Anhui, Jiangsu, Henan, Shandong, Shaanxi and Gansu - were threatened.
China suffers from an uneven distribution of its water resources, where per person water availability in the north is less than a quarter of that in southern China.