Overall consumer prices in April were up 2.5% from a year earlier, government data showed. It was the first time since September 2008 that inflation topped 2%, excluding the impact of sales-tax increases. It was also the fastest rise since 1991.

Japanese companies have had long experience with deflation, or persistently falling prices, and have been cautious about upsetting the nation’s price-sensitive consumers. But some say they have no choice now.

On Monday, the soft drink unit of Suntory Holdings Ltd. said it planned to raise prices on more than half its products, including bottled water and canned coffee, starting in October. Prices will go up by 6% to 20%.

“Manufacturing costs are worsening significantly because of the surge in raw-material prices caused by tight global demand,” Suntory said, also citing the recent fall in the yen and higher plastic-recycling costs. “It has exceeded the level a company can absorb by its own efforts.”

Bank of Japan data released Monday showed prices paid by corporations for materials and commodities such as oil and steel in April were up 10% from a year earlier, the fastest rise since 1981 when comparable data became available.

Policy makers are reluctant to tighten monetary policy to control inflation because they see price increases in Japan as driven primarily by higher costs for energy and raw materials. In the U.S., those factors have combined with strong demand to lift inflation above 8%, triggering rate increases by the Fed.

In April, Japan’s consumer prices rose 0.8% when excluding volatile fresh food and energy prices.

Economists say 2% inflation is unlikely to last because consumers aren’t seeing enough wage growth to accept higher prices.

“Rigid labor practices in Japan mean less labor mobility, and therefore less likelihood for wage increases, which also lowers the possibility for inflation,” said

Nobuko Kobayashi,

a retail-industry specialist at consulting firm EY. “Japan is likely to remain deflationary, seeing fewer price hikes and wage increases than its Western counterparts.”

In a speech May 13, Bank of Japan Gov.

Haruhiko Kuroda

said Japan is recovering more slowly from the Covid-19 pandemic than the U.S. and Europe. He said price increases were driven by energy costs and lacked sustainability, while there has been no sharp increase in medium-to-long-term inflation expectations.

“The role of monetary policy in these circumstances is to firmly support the recovery of aggregate demand by providing accommodative financial conditions,” he said.

The bank’s forecasts show that core inflation will likely come down to around 1% in the years ending March 2024 and March 2025.

Write to Megumi Fujikawa at megumi.fujikawa@wsj.com