There will be no fundamental changes in the placement of the SIM card slot or buttons on the iPhone 5 handset, according to puported mockups of cases for the forthcoming handset.

The images, obtained by the HardMac website from what it claims is a "reliable source", show prototype cases based on design specifications provided by Apple.

The SIM card slot and buttons are in the same place as they are on the iPhone 4. While this is not entirely surprising, the cases would also seem to cast doubt on suggestions that Apple was going to abandon the steel outer frame in the new device.

However, the site does stress that the information has not been officially confirmed.

The iPhone 5 is expected to be announced at the WorldWide Developer Conference in San Francisco in June. Other rumours about the design of the device include the use of an A5 chip and perhaps use a 'logo antenna', where the antenna is placed just behind the logo on the back of the device.

Despite earlier rumours about Near Field Communication (NFC) technology to enable contactless payments, reports from early this week suggest that the iPhone 5 won't have this feature.