Japan's Ministry of Agriculture, Forestry and Fisheries has been studying possible risks to the country's food supply and has identified the war in Ukraine as the most serious threat.
The ministry says in a report released on Tuesday that Russia's invasion of one of the world's biggest grain exporters is a significant risk to food security.
Japan depends heavily on imported grains for animal feed, and prices have been soaring. It also imports material for fertilizers, and that supply has become unstable too.
Agriculture minister Kaneko Genjiro said these are issues that have to be addressed quickly.
The ministry says that any further increase in the price of wheat, soybeans or vegetables would have a major impact on the stability of the food supply.
The report also warns of a looming issue with Japan's workforce. It warns the country's changing demographics mean there is likely to be a shortage of people to farm vegetables, fruit, livestock and fishery products.