Japan's competition watchdog has raided some of the country's biggest ice cream makers for allegedly forming a cartel to raise prices.

Some of the firms, including Meiji and Pocky maker Ezaki Glico, said this week that they have been subject to an "on-site inspection" by the Japan Fair Trade Commission (JFTC) amid suspicions that they fixed prices for frozen desserts.

The JFTC said it is not releasing a statement regarding the investigation.

The companies are suspected of inflating ice cream prices beyond increases in raw material costs, even as the country faces a hot summer with record-high temperatures.

The six firms that were raided on Tuesday were Meiji, Morinaga Milk Industry, Lotte, Morinaga, Ezaki Glico and Akagi Nyugyo.

The BBC has contacted the companies for comment.

The firms improperly raised prices of popular desserts "several times by 5-10% over the years", according to Japanese broadcaster NHK, citing anonymous sources.

The brands distribute their products wholesale to supermarkets and convenience stores across Japan.

Morinaga Milk, Glico and Meiji said in separate statements that they would cooperate with the authorities' investigation.

"As reported by some media outlets today, our company has been subject to an on-site inspection by the Fair Trade Commission on suspicion of violating the Antimonopoly Act in connection with the setting of sales prices for ice cream and other products," Meiji said.

"We take this inspection very seriously and will cooperate fully with the Fair Trade Commission's investigation," the Hello Panda snack maker wrote.

Glico said: "We will respond in good faith to the Fair Trade Commission's investigation and cooperate fully."

Earlier this year, Japan unveiled a new name for days that reach 40 °C (104F) or above, after the country experienced its hottest summer on record in 2025.

The term - kokushobi - has been translated as "cruelly hot", "brutally hot" or "severely hot" day by Japanese and international media.