Apple is working on new gadget functions or killer features that likely will be deployed in time for the rumoured 2013 release dates of the iPhone 5S and the iPhone 6, one analyst said.

The iPhone 5S represents Apple's incremental upgrade of last year's iPhone 5 while the iPhone 6 is widely speculated as the tech giant's answer to exploding phablet offering of its chief rival, Samsung.

Both upcoming devices, according to Morgan Stanley analyst Katy Huberty will be laced with the so-called 'killer features' to gain more traction with top-notch Android rivals that include the Galaxy S4, the HTC One, the Sony Xperia Z and two gadgets believed to be coming out later this year - Google's Nexus 5 and Samsung's third-gen phablet, the Galaxy Note 3.

In her new note to investors, Ms Huberty said that major improvements are currently underway on existing Apple services that would lead to better user-experience in the upcoming rendition of the iCloud and the Apple Map.

While not pointing specifically to the rumoured iRadio, the analyst is convinced a similar service will be unveiled by Apple via the Worldwide Developers Conference on June, to be fully-functional by the time the iPhone 5S and the iPhone 6 are released.

She hinted too that Apple's passbook will get a significant boost this year, likely morphing the service to a full-pledged digital wallet that is fuelled by near-field communications (NFC) technology.

All these will be lumped as Freemium Apps, which are available for free downloads with Apple realising revenues through in-app purchases and advertisements.

"We believe Apple could charge either developers or users for some of these services, which could boost Apple's annuitized revenue stream and better monetize its large user base," Ms Huberty was reported by Apple Insider as saying.

Her new projections came out as a new report suggests that Apple would likely delay the release dates of the iPhone 5S, the budget iPhone and the iPad Mini 2 due to a number of production glitches.

However, Ms Huberty is convinced that Apple can actually forego major design upgrades for its devices, accelerate their release and still achieve higher revenues, courtesy of the premium services that can be packaged as killer features for both the iPhone 5S and the iPhone 6.