Wheat prices are poised to increase for the third time in a year, adding to inflation as Prime Minister Shinzo Abe's economic stimulus weakens the yen and boosts costs.

Foreign wheat sold by the government to flour millers will probably rise about 5 percent in October from ¥54,990 a metric ton on average, according to the U.S. Wheat Associates.

The Agriculture, Forestry and Fisheries Ministry will decide on prices this month, based on purchasing costs in the six months through August, said Sunao Orihara, the ministry's director of grain trade.