Google is to venture further beyond its core search engine business with a new instant messaging and voice calling service that takes it into greater competition with established telecommunications companies round the world as well as a growing list of rival online services.

The new service will be called Google Talk, according to a person familiar with the company's plans. It puts Google in competition with the more established instant messaging services of AOL, Yahoo! and Microsoft's MSN, which have also added voice and video to their services in recent months.