After Apple rejected a Sony e-reader application for the iPad from its App Store for not complying with the rules, Sony has fired back and suggested it is hoping to be able to exit Apple's iTunes Music Store.

Michal Ephraim, chief executive of Sony Computer Entertainment, spoke with Australia's The Age about the impending launch of its Music Unlimited service in that country. Music Unlimited debuted in late 2010, and Sony hopes the streaming subscription product will take on Apple's iTunes by offering a different approach to digital music sales.

But in the future, Ephraim hopes that iTunes isn't even part of the equation. He questioned whether Sony would need to partner with Apple and sell music through iTunes if its new service gains enough traction.

"If we do [get mass take-up], then does Sony Music need to provide content to iTunes?" he said. "Currently we do. We have to provide it to iTunes as that's the format right now."

He continued: "Publishers are being held ransom by Apple and they are looking for other delivery systems, and we are waiting to see what the next three to five years will hold."

Tensions have grown between Sony and Apple since earlier this month, Apple rejected an e-bookstore application from Sony from its digital App Store for the iPad. A story in The New York Times suggested the rejection showed that Apple is "further tightening control of its App Store."

But Apple responded to that report and insisted that it has not changed its developer terms or guidelines. "We are now requiring that if an app offers customers the ability to purchase books outside of the app, that same option is available to customers within the app with in-app purchase."