Handset will store 500 songs.

KDDI, Japan's second-largest mobile operator, is to launch in June a mobile handset with a built-in Sony Walkman music player capable of storing some 500 songs.

The Walkman Keitai W42S handset, which KDDI developed jointly with Sony, will be able to operate for about 30 hours on a single charge when used as a music player and will retail for about ¥ 20,000 ($179.15).

The handset's launch comes amid intensifying competition among Japanese carriers to provide music and other entertainment content to attract subscribers.

Local media recently reported that Tokyo-based Internet service provider Softbank and Apple are jointly developing handsets with built-in digital music players capable of directly downloading songs from Apple's iTunes Music Store, although neither company has confirmed such reports.

Meanwhile, NTT DoCoMo, Japan's biggest mobile phone operator, and Microsoft recently announced the launch this summer of two handsets that will support Microsoft's Windows Media Audio and Windows Media Digital Rights Management 10 for portable devices.