Apple is rolling out three screen sizes for the new iPhone 5S and its low-cost version but the reconfigure will possibly push back the earlier preview date of June 20 and the subsequent commercial release on first week of July.

It could be late on the tech giant's iPhone production calendar but according to Topeka Capital Markets analyst Brian White "Apple is coming around to the fact that one size per iPhone release does not work for everyone."

As a result, the company would opt to adjust its production schedule to accommodate the new screen sizes for the next-generation iOS smartphone that last year Apple had upgraded to 4-inch via the iPhone 5.

Now, there is a strong possibility that the iPhone maker will renege from its earlier assertion that 4-inch is the ideal size for the iPhone 5S.

The company, according to Mr White, has come to the realisation that "offering consumers an option has the potential to expand the company's market share."

Analysts have been harping on the likelihood that Apple is revising its iPhone model in order to preserve its market dominance and encroach on other territories that were previously ruled by Samsung and Nokia.

That move, Mr White said, will be reflected on new iPhone models to come out by middle of 2013, which will sport two new screen sizes apart from the original 4-inch dimension.

No specifics were offered by the Topeka analyst but it is highly likely that Apple will resurrect the old iPhone screen size last seen through the iPhone 4S and add a new measurement that exceeds the 4-inch iPhone 5S.

The same Topeka note affirmed earlier projections that Apple is all set to conquer the emerging markets with the addition of a cheaper iPhone model to its gadget stable.

However, the possibility is remote that Apple will sell the budget iPhone below the $US300 mark.

"Those expecting a $US150 to $US200 iPhone will be disappointed ... a price tag of $US300 to $US350 now makes more sense," Mr White was reported by BGR News as saying.

The affordable iPhone pricing is in line with Apple's plan of protecting both its premium brand and profit margin, the analyst added.