Sony is to launch a service that allows Japanese gamers to play some titles over the internet that were previously restricted to ad hoc network connections with people nearby.

The 'Adhoc Party for PSP' service will work through the PlayStation 3 (PS3) so gamers without the console won't be able to make use of it. By downloading an application through the PlayStation Store, the service will be enabled and games with an ad hoc gaming mode can be played with friends over the internet.

The service won't support all titles with an ad hoc mode. Initially 'Monster Hunter Portable 2nd Generation', which is hugely popular in Japan, will work with the service and other games are promised in the future including 'Phantasy Star Portable'.

Gamers using the service will first enter a lobby where they can see other players online and chat with them. During game play, voice chat will be possible through Sony's PSP wireless headset or PlayStation Eye camera.

The beta version of the software will be offered free of charge in Japan from October 30. Launch plans for other markets were not announced.