Apple is looking to use a plastic flexible OLED screen for its upcoming iWatch, which can be bent.

The iPhone maker is testing OLED screens in 1.3in, 1.4in and 1.5in screen sizes for the forthcoming gadget, Korean publication ChosunIlbo reported.

Reports also reveal that Apple has developed a prototype of the iWatch with a 1.5in screen and it is likely that the iPhone maker may source the flexible OLED screens from Korean firms including LG and Samsung.

Last month, Samsung launched its new Galaxy Gear smartwatch, which incorporates a small 1.63in Super AMOLED screen that allows users to speak into their wrist watch.

Other manufacturers involved in smartwatch race include Chip maker Qualcomm Pebble, LG and Microsoft.

According to a new report from Canalys, the global smart watch shipments are expected to surpass five million units during 2014, a 900% rise over anticipated shipments for 2013.

Another report from ABI Research reveals that revenue generated by wearable wireless devices is expected to surpass $6bn by the next following years.