A large delegation of Burundi's last active rebel group is in the capital to discuss implementing the ceasefire.
Last September's ceasefire has often been broken
This is the biggest group of top Forces for National Liberation (FNL) officials to go to Bujumbura since they took up arms 14 years ago.
Hundreds of FNL supporters welcomed the 17-member team at the airport.
The ceasefire was agreed last September but both sides have accused the other of violating it. Some 300,000 people have died during Burundi's conflict.
Previous peace talks with the FNL have been held in the Tanzanian city, Dar es Salaam.
The FNL had refused to join the monitoring team, demanding immunity on its members.
It is not clear whether this has been granted but Tanzanian and South African diplomats have been urging FNL officials in return to Burundi.
FNL's estimated 3,000 fighters are due to disarm in a process to be supervised by African Union and United Nations.
Rubin Tubirabe who is leading the FNL team, blamed the government for the delay of implementation of the ceasefire agreement.
"The FNL does not want any more fighting but it wants lasting peace for the people in Burundi," he said.
FNL leader Agathon Rwassa is not among the monitoring team, which includes government representatives.
The BBC's Kazungu Lozy in Bujumbura says residents have welcomed the FNL move and are now hopeful that the shaky relations between the government and the rebels, even after signing of the ceasefire, will improve.