Production lines for both the iPhone 5S and its budget version has commenced humming, a new report said, supporting an earlier story that Apple is set to release the two handsets on June at the earliest.

According to Apple Insider, Foxconn has started the manufacture of the upcoming iPhone refresh, citing a blog report by Japanese blog site MacOtakara.

The early start was made possible by the similar design that Apple is employing with the iPhone 5S, keeping up with the tech giant's practice of maintaining much of the handset specs that the S edition will replace.

"Little to no tooling is needed to manufacture the two models on the same production lines," the same report said.

It supported the projections earlier made by KGI Securities that the iPhone 5S and the cheaper edition are essentially of one kind, differing only inside the guts and body material.

For instance, the iPhone 5S will showcase the A7 processing chip while the more affordable make will keep the A6 CPU. The former is also housed in a metal chassis while the latter will have to make do with plastic, with the object of achieving a starting price point of $US350.

This early, the iPhone production mode is in a ramped up level, the same report said, possibly to meet Apple's target of distributing the two devices by June at the earliest. However, some reports have suggested that should delays will hamper the manufacture end, Apple will be forced to launch on August.

Regardless, the new report suited with an earlier assertion by Jefferies analyst Peter Misek that Apple will begin producing the new iPhones on March 2013.

Also, the rush is seemingly connected to a recent move by Japanese telco NTT DoCoMo to include iPhone on its service packages, adding to its largely Android lines of smartphones, added the MacOtakara report.

Apple's 2013 plans include deeper incursions on China's mobile market, which explains too its spirited effort of producing big numbers of iPhone with speed.

Reports suggest that Apple is working to secure a close partnership with China Mobile, considered as the world's largest telecommunication firm. With an estimated subscribers' base of 700 million, the firm is a natural magnet for Apple as it sets out to reclaim the more than 30 per cent shares value it lost in the past few quarters.

The budget iPhone that the tech titan is making is mostly geared for release on emerging markets, with China as the prime destination, analysts said.