Prices of goods traded among companies in Japan rose for the 6th consecutive month in August.
The increase was mainly due to higher costs of crude oil and other raw materials.
The Bank of Japan said on Monday the producer price index gained 5.5 percent last month from a year earlier. The figure remained at the highest level since 2008 for the second month in a row.
Prices of crude oil and copper remain high as the resumption of economic activities worldwide drives demand. Similar trends are seen with lumber, aluminum, nickel and other raw materials.
BOJ officials say industries such as food and steel are starting to pass on the higher costs to their clients.
But they say the outlook is uncertain because raw material prices are sensitive to coronavirus infection situations around the world.