With a 4-inch screen size and a host of killer features, the current iPhone template is delivering what gadget consumers generally require, Apple CEO Tim Cook declared.

Rumours of iPhone's screen stretching beyond four inch and other crazy functions and features may abound at the moment but Apple is firm on its stand that talks of numerous iPhone models is confined at the moment to the drawing boards.

In an interview with Walt Mossberg of AllThingsD, Mr Cook downplayed the need for diversifying the current iPhone template despite the emerging trend of big-screen smartphones, triggered by Samsung's introduction of the Galaxy Note phablet series.

He acknowledged the fact that consumers are drawn to the massive screen offerings of devices like the Note 2, the Galaxy S4 and HTC One but insisted that so long as technology tradeoffs exist, Apple will not take the plunge. Not this year anyway.

First, Apple needs to address key concerns like "the white balance, the reflectivity, battery life ... and the longevity of the display," which according to him are points that consumers look forward to deliver maximum benefits.

It could be that "customers are clearly looking at the size, but they also look at things like 'Do the photos show the proper color?'" the Apple big boss explained.

While it is true that the company had previously dipped its fingers on diversified products, in the case of different iPod models, Mr Cook insisted that the iPhone product development is very much different, hence there is no point for comparison.

Simply put, coming up with more models aside from the iPhone 5 entails a complicated procedure that takes time and resources. It is a daunting task, Mr Cook said.

Nonetheless, the Apple chief did not totally dismiss that the iPhone portfolio will be expanded in the near future, pointing to his earlier statements that the company is getting ready to deliver giant surprises by fall this year and to continue for the rest of 2014.

It is highly likely that a totally different iPhone flagship model will come out as Mr Cook hinted that iOS smartphones with fresh features and tagged with various price points could be ventures that Apple could seriously look into.

"That doesn't shut off the future," Mr Cook said.

He refused, likewise, to discuss the rumoured release dates of upcoming iPhone refreshes, which analysts said would come in the form of the iPhone 5S, set for a September rollout this year, and the iPhone 6, poised for a June 2014 debut.

Instead, Mr Cook pointed to Apple's Worldwide Developers Conference in San Francisco, California, which kicks off on June 10, for further details.