London - Epic Games, the publisher of the popular video game Fortnite, filed a complaint on Tuesday with Britain's competition monitor accusing Apple of "monopolistic practices".
The US video game developer told the Competition and Markets Authority that Apple was guilty of "anticompetitive behaviour and prohibitively restrictive rules governing the distribution of apps and payment processing".
This was a "clear violation" of British law, it said.
Apple's actions "forbid users and developers respectively from acquiring or distributing apps through marketplaces other than Apple's App Store". The payment of commissions sometimes reach 30 percent of revenues.
Epic has already launched other legal proceedings in the United States, the European Union, Australia and Britain against both Apple and Google.
Epic says it is "not seeking monetary damages" but rather regulatory decisions from authorities to force Apple to amend its practices.
Apple defended its position and said Epic's request to open up the iOS app ecosystem would weaken security.
"Now that they have achieved massive success through the App Store, becoming a multibillion pound corporation, Epic wants to operate under a different set of rules than the ones that apply to all other developers," Apple said in a statement to AFP.
"The result would be weakened privacy and data security protections for our customers, and we think that's wrong."
In August, Epic tried to circumvent Apple's payment technology on its iOS operating system.
The iPhone manufacturer immediately removed Fortnite from the App Store, citing a breach of contract between the two companies.
The social media giant Facebook and streaming service Spotify have also criticised Apple for stifling competition. They argue it imposes rules on external developers that it does not apply to itself.
The European Commission has opened several investigations into the US computer manufacturer, which has defended its closed ecosystem by saying that this protects users' data security.
Apple and other US tech giants, including Google, Facebook, Amazon and Microsoft, also face the introduction of possible new obligations and fines under a new legislative proposal by the European Union, the Digital Markets Act (DMA), which is aimed at restricting their dominance of the sector.
Agence France-Presse