The agriculture ministry plans to import an extra 7,000 tons of frozen butter for commercial use to stabilize prices amid a domestic shortage, according to ministry officials.

The country's first emergency butter imports in two years are set to be its biggest on record.

Production in Japan of milk, the precursor to butter, has dwindled due to last year's sweltering summer and the decline in the number of dairy farmers, the officials said.

The ministry will accept bids from overseas suppliers from later this month through early June, with a view to getting the butter to food producers by the end of November, in time for the Christmas cake rush.

It manages the supply of dairy products to businesses such as confectionery producers and trade houses through a state trade enterprise.

"We will continue to monitor dairy demand and price movements and work to ensure a stable supply," a ministry official said.