Over the past year, it has looked increasingly likely that regulators around the world will soon start cracking down on Apple and Google's strong control of their respective mobile app markets. South Korea has now become the first country to make a move to curb this power.

On Tuesday, the Wall Street Journal (paywall) reports, the country's National Assembly passed a bill that prohibits app store owners from banning developers from using alternative payment systems in their apps. The legislation had previously been criticised by both Apple and Google.

This is exactly what Epic, Spotify and other companies have been asking for, so they don't have to pay the usual 30% revenue fee to the app store owner and can also handle disputes, incorrect payments and other details themselves, instead of having to rely on that company to step in and arbitrate.

Google tells The Verge that it costs money to develop Android and that it will review its options in the coming weeks. Apple has yet to comment following the passing of the law, but beforehand it said the law could have negative consequences for users and developers.

"The [law] will put users who purchase digital goods from other sources at risk of fraud, undermine their privacy protections, [and] make it difficult to manage their purchases," Apple's statement reads.

"We believe user trust in App Store purchases will decrease as a result of this proposal - leading to fewer opportunities for the over 482,000 registered developers in Korea."

Aware of growing discontent, Apple has been gradually softening its stance regarding control of the App Store over recent years, allowing developers to appeal against its decisions and lowering fees in some cases. But it has stuck to the principle of being able to control payment methods.

According to the New York Times (paywall), lobbyists for both companies have been trying to convince US lawmakers that the Korean law could be a violation of the free trade agreement between the countries.

This article originally appeared on M3. Translation (using DeepL) and additional reporting by David Price.