Google has added voice and video chat features to Gmail, allowing users to set up live chats with contacts through a webcam or microphone.

The new service will be introduced as an add-on to the Gmail interface. It will not be released as a stand-alone application, and users will need to download a browser plug-in in order to install the service.

Google said that the 2MB plug-in will work with the latest Mac OS and Windows versions of Internet Explorer, Firefox, Safari and Google Chrome.

"From viewing videos on YouTube to screening family events, people love being able to watch something exactly as it happened," wrote Google product manager Serge Lachapelle in a blog posting.

"And as webcams have become popular, more and more of us realise that video is the next best thing to an in-person conversation."

Google's latest move gives the company another weapon in its ongoing battle in the hosted communications market.

As Google's messaging and mail systems gained popularity at home and in the workplace, the company began to see competition from traditional enterprise giants IBM and Microsoft, which transformed the Lotus and Exchange platforms into hosted offerings.