Talks between the Burundi government and former rebels have been extended because of disagreements over the date of scheduled elections.
Many thousands of Burundians have fled a decade of conflict
Polls are due in October but the government wants them put back until the former rebels have been disarmed.
The Forces for the Defence of Democracy has withdrawn from a power-sharing government and is opposed to any delay in the elections.
The mainly Hutu FDD has been fighting for an end to ethnic Tutsi domination.
The talks in the South African capital Pretoria were supposed to end on Sunday but continued on Monday.
'Running after dates'
"We are ready for elections as scheduled. We do not want any delay," said FDD leader Pierre Nkurunziza.
The FDD pulled out of the transitional authority earlier this month, saying it had not been given the jobs agreed in a peace deal.
Last week, President Domitien Ndayizeye called for a postponement.
"We are not running after dates. We need free and fair elections in full security," he said.
"Former armed groups will be turned into political parties and will go to the polls. So before we go to elections, the population, militia groups and what we call 'militant combatants' must all be disarmed."
The polls are supposed to bring an end to an 18-month transition period, under a deal brokered by Nelson Mandela.
Mr Ndayizeye, a Hutu, took over from Tutsi Pierre Buyoya.
About 300,000 people have been killed in 11 years of conflict.
The UN Security Council voted last week to send some 5,500 peacekeepers to Burundi.