Apple has announced that the white iPhone4 cannot be made available until later this year due to technological challenges in its manufacture.

A Telegraph report says the Chinese glass-etching firm that Apple has apparently employed is reportedly struggling to fabricate the coating to the specified thickness and colour.

The iPhone 4, launched earlier this year in black, has presented a series of problems to Apple. These include widespread complaints over the device losing its network signal when customers grip the device's bottom left corner- covering one of the antennae.

After initially asking users to "avoid holding it in that way" and recommending they go out and buy "one of many available cases", Apple eventually offered users a free case or a full refund.

In a statement announcing the delay of the white model, Apple said availability of the iPhone 4 black models will not be affected by the fabricating difficulties.