The United Nations estimates about 650,000 people have been displaced by violence within Central African Republic, while nearly 300,000 have crossed into neighboring countries.
Bernard Acho Muna, who chairs the inquiry set up by the UN Security Council in December, said a mission would leave Geneva on Monday for Central African Republic, where it would interview Christian and Muslim victims of violence and draw up a list of suspects for eventual prosecution.
He told a news briefing he hoped the investigation would signal to people making what he called "hate propaganda" that they should not embark on greater violence, Reuters reported.
"We have also heard reports of genocide. But one thing I can tell you from my Rwandan experience is that there is definitely a question of propaganda already, hate propaganda, that is usually a very bad sign when they say propaganda."
"We don't wait until genocide is committed and then we call for prosecution. I think it is in our mandate to see how one can stop any advances toward genocide," Muna said.
The commission is expected to arrive in Bangui on Tuesday.
Thousands of people have been killed since the Seleka, a coalition of northern rebels, seized power a year ago and launched a campaign of looting, torture and killing in the majority Christian country.
Since the resignation of Seleka leader Michel Djotodia as interim president in January under intense international pressure, Christian "anti-Balaka" militias have stepped up reprisals against the Muslims.