The higher outlook was based on China's most recent agriculture census, the ministry said in its monthly China Agricultural Supply and Demand Estimates report.
China, the world's second largest producer of corn, sharply revised higher its corn output data for the past 10 years last November following its third national agricultural census.
The ministry on Friday also raised its forecast for corn consumption in the year that began in October to 285.28 million tonnes, up by 34.48 million tonnes from its previous estimate.
Corn imports for the year were seen at 1.5 million tonnes, down from the previous forecast of 2.5 million tonnes, the report said.
China's 2018/19 corn ending stocks deficit was seen at 26.5 million tonnes against the previous forecast of 33.31 million tonnes.
Soybean production for 2018/19 was forecast at 16 million tonnes, up from a previous forecast of 15.8 million tonnes.
Soybean consumption for the year was seen at 102.8 million tonnes, down 3 percent from 107 million tonnes in the previous year, as a series of deadly African swine fever outbreaks and lower protein levels in animal feed pushed down demand for soymeal, the ministry said in the report.
China has confirmed about 100 cases of African swine fever across 23 provinces since early August last year. The disease, for which there is neither a cure nor a vaccine, is deadly to pigs but does not harm people.
(Reporting by Hallie Gu and Tom Daly; Editing by Joseph Radford and Richard Pullin)