Facebook Lite appears to be a cut-down version of Facebook and is aimed at countries where broadband is limited.
The site is currently on trial in India and it is thought there are plans to extend this to China and Russia.
In a statement Facebook said the new service would be a "faster, simpler version similar to the Facebook experience you get on a mobile phone".
"Facebook Lite is a fast-loading, simplified version of Facebook that enables people to make comments, accept friend requests, write on people''s walls, and look at photos and status updates," the statement continued.
"We are currently testing Facebook Lite in countries where we are seeing lots of new users coming to Facebook for the first time and are looking to start off with a more simple experience."
Facebook claims to have more than 250 million active users, although more than 72% of these are in Europe and North America, where fast broadband internet connections are common.
Mobile world
In developing countries, where the infrastructure for broadband is limited, mobile phones are emerging as the dominant way for the internet to develop. A cut-down version of Facebook that loads and runs effectively on a mobile platform would enable the firm to expand into these markets.
The news of Facebook Lite comes just days after Facebook acquired content-sharing service FriendFeed.
The service offers a "real-time" search engine that lets users know what is happening currently on any given subject.
The purchase caught many industry watchers by surprise, even though the two companies had been talking on and off for the past two years.