A plane scheduled to take government officials, opposition leaders and others to Gabon for the talks failed to arrive in the Gabonese capital of Libreville on schedule, Voice of America reported.
The delegation representing rebels who control a third of the country arrived late Monday.
Government sources said the rebels are just 54 miles from the Central African capital of Bangui.
A multinational African force currently stands between the rebels and the capital, VOA reported.
The rebels are demanding President Francois Bozize step down and Bozize agreed last month to unconditional talks to form a coalition government.
He also said he will not run for a third term in 2016.
The rebellion is the third major one against Bozize since he won election in 2005. Two years earlier, he seized power in a military coup.