Most opposition parties have boycotted the talks and called for a general strike on Wednesday to put pressure on Kabila
The Constitutional Court in Democratic Republic of Congo said on Monday it had approved a petition by the electoral commission to delay a presidential election set for November, allowing President Joseph Kabila to remain in office until April 2018.
Kabila was due to step down in December when his two-term mandate expires and his opponents say they fear he intends to first prolong his term in office and then change the constitution to enable himself to run again.
The ruling coalition and part of the opposition say the vote should be held in April 2018 and on Monday their agreement was ratified by delegates at cross-party talks in the capital, one party leader said.
Most opposition parties have boycotted the talks and called for a general strike on Wednesday to put pressure on Kabila. They are likely to be further angered because the court appeared to breach its own quorum rules in reaching Monday's decision.
European Union foreign ministers said on Monday they would prepare economic sanctions against Congo unless it held presidential and parliamentary elections next year.
Kabila says he will respect the constitution but has not made clear if he plans to find a way to run again. Last year, the presidents of neighbouring Congo Republic and Rwanda won referendums to change their constitutions to stand for third terms.