More than 100 members of opposition groups from inside and outside Syria took part in the two-day meeting, which began Wednesday, in the Saudi capital of Riyadh.
The meeting was aimed at welding the opposition groups into a unified team for potential talks with the government of President Bashar al-Assad.
Abdulaziz al-Sager, the Saudi chairman of the meeting, said at a news conference on Friday that the opposition groups agreed to meet with Damascus officials to find a solution to the almost five-year-long conflict in Syria.
"There will be a meeting decided by (United Nations envoy Staffan) de Mistura in January," Sager said, adding, "This will take place in the first 10 days of January."
The participants also issued a statement at the end of the meeting over the future negotiations, but called for President Assad and his aides to "quit power with the start of the transition period," which was set at the Vienna talks in November.
Representatives of the Ahrar al-Sham militant group reportedly left the Riyadh meeting in the final hours.
The group said in a statement that its withdrawal was an objection to the a major role given to the National Coordination Body for Democratic Change, a Damascus-based opposition group. The group said the militants operating inside Syria were under-represented at the meeting.
Despite Ahrar al-Sham’s withdrawal, the statement was eventually signed by all the participants, Press TV reported.
The Takfiri Daesh terrorist group, the al-Qaeda-affiliated al-Nusra Front and a Syrian Kurdish group that has taken control of areas in north Syria had not been invited to the talks in Riyadh.
The meeting came after two rounds of international talks on the conflict in Syria in Vienna on October 30 and November 14. The participants agreed in the last negotiations to meet again in “approximately one month” to review progress toward a ceasefire and the start of a political process in the violence-scarred country.