Apple's new subcription service within the App Store could lead to legal scrutiny in the US, according to experts.

The Wall Street Journal reports that some within the legal profession have concerns about the way the subscription service works.

Apple's new rules state that app publishers must remove any links to non-App Store purchasing options from within their apps. They can continue to sell content from within the app, though this must go through Apple, which takes a 30 percent cut.   

Additionally, if the publishers of the apps sell subscriptions outside of the App Store, Apple must be able to offer the same deals within the App Store at the same price, or less.

Shubha Ghosh, an antitrust professor at the University of Wisconsin Law School, told WSJ that if Apple is seen to be exerting "anti-competitive pressures on price" or if it has enough of a dominant position in the market, there could be anti-trust implications for the company.

However, another legal expert quoted by the WSJ said that he doubted that Apple had enough of a dominant position currently to warrant anti-trust scrutiny. Herbert Hovenkamp, an antitrust professor at the University of Iowa College of Law said that if Apple were selling 60 percent or more of digital subscriptions through its App Store "then you might move into territory where an antitrust challenge would seem feasible."

The new rules will have significant implications for Amazon. To meet Apple's guidelines, Amazon must remove its 'Shop in Kindle Store' link from its Kindle application.

Amazon has yet to issue a comment on the matter but other app publishers are unhappy with the new rules. The Register reports that Rhapsody, a subscription-based music-streaming service, feels the arrangement is unworkable.

"An Apple-imposed arrangement that requires us to pay 30 per cent of our revenue to Apple, in addition to content fees that we pay to the music labels, publishers and artists, is economically untenable," the company said in a statement.

Many European newspapers were unhappy with Apple's demands concerning subscriptions to apps before the new policies were announced, as Digital Arts reported in January.