The facility allows the Red Cross and Red Crescent charities to send SMS messages to every switched-on handset in a specific area by drawing its shape on a computer-generated map.
It also automatically sends back appropriate replies to incoming texts.
The charities say they hope to complete the expansion within nine months.
However, they will first require the co-operation of local mobile networks and authorities.
"It's been doing an excellent job in Sierra Leone, sending out in the region of 2 million messages per month, helping the communities there to prepare themselves, try to avoid getting infected, and then if they do, to know what to do about it," explained Robin Burton from the International Federation of Red Cross and Red Crescent Societies (IFRC).
