The 15-year-old girl was attacked in the Laurel Glen area at the Stewartstown Road on Saturday evening.
It is understood she spoke with a man in the Suffolk Road or Woodbourne Crescent area at around 8pm.
He is thought to be in his 40s or 50s and was wearing a dark jacket and trousers or jeans. He is between 5'8" and 5'10" and of average build.
His hair was short and thought to be either brown or ginger, and it is understood he may also have been wearing glasses.
Anyone who saw the girl walking in the Suffolk or Stewartstown Road areas either alone, or with the man, asked to contact police.
Meanwhile, police have put on extra patrols in the area, following a meeting between the PSNI Area Commanders and community representatives.
Local Sinn Féin MLA Jennifer McCann said the meeting was important to impress upon the police "the seriousness of this attack".
"But also to ensure that everything has been done to bring this perpetrator to justice," she added.
"People are very, very angry and very, very concerned. This is not the first time an attack of this nature has happened in that particular area over a number of years and we will, as community representatives, be going to see what we can do to make the area safe."
Community development worker Stephen Magennis said anyone who knows what happened should come forward.
He said: "It's very important that the information from the community comes to the PSNI so that if there's to be a conviction, that's the only way it's going to happen.
"It's essential that whoever is involved in any attack like that is arrested because they're a danger to society, they're a danger to many people out there and, if they're not caught, it could happen again."
The community workers say there is anger and concern throughout the area, and have called for young people to be vigilant about their own safety.