The Japanese authorities believe Apple and Google may be engaging in practices that undermine competition in the app market, Nikkei reported.

The Ministry of Economy, Trade and Industry looked at how the companies, as well as others who control platform on which apps are sold, are able to control what developers can and cannot do.

For instance, it found that they limit the pricing freedom of developers as well as the payment methods they can accept, which may not directly violate anti-monopoly law but still “lead to elimination of competitors”.

Japan’s Fair Trade Commission will investigate further and “may choose to conduct on-site inspections if there is sufficient suspicion of regulation breach,” the report quoted a high-ranking official as saying.

Apple’s policy in particular was criticised. For one, it charges a 30 per cent commission on any purchase made through an iPhone app, which developers refer to as the “Apple tax”, while preventing alternative distribution channels.

“This practice may be deemed abuse of an advantageous position under the anti-monopoly law,” the report said, and could “lead to market control that allows the company to eliminate competition.”

What’s more, if a user asks for a refund, Apple does not give the 30 per cent fee back to the developer, which means they need to return the money to the user from their own pockets.

The report was created by a study group established at the ministry in January and included a survey of developers that was conducted jointly with the Fair Trade Commission.

Earlier this year, EU competition commissioner Margrethe Vestager accused Google of “stifling competition and innovation” by using the Android platform to sideline app rivals.