According to a recent Wall Street Journal report, the US Department of Justice and Federal Trade Commission are looking into concerns which app makers have expressed about Apple’s decision to take a 30 percent cut on revenue from all online subscriptions.

Apple, which launched the new subscription service last week, has come under fire over the subscription terms for sale of content through its iPhone and iPad.

The new subscription service – which will take effect from June 30 - will essentially stop magazines and newspapers linking out to external websites, insisting that all in-app subscription payments go via the App Store.

The changed terms of Apple’s subscription service imply that publishers will not be able offer links within apps to websites where customers could purchase their products or offer a more attractive deal from outside of the App Store.

The anti-trust regulators will chiefly ascertain whether the Apple’s new ‘subscription tax’ decision amounts to a violation of the law; as the company will be forcing publishers to use its own subscription system for collection user payments.

While the investigations against Apple are reportedly still ‘preliminary’ in the US, the International Newspaper Marketing Association in Europe has also called for an official investigation into the matter, cautioning that “publishers simply can't afford to invest in new technology, products and services when the platform charges them 30% of total revenue.”