"Our technical team and of other oppositions will meet today at 15:30 [13:30 GMT] with the UN technical team to discuss the election basket," Khalidi said.
Technical discussions between the UN team and the Syrian sides started at the previous round of Geneva talks, focusing primarily on the constitution.
At this round, the agenda is expanding to cover all baskets of issues, including governance, elections and anti-terrorism.
Representatives from all opposition groups, namely the Cairo and Moscow platforms and the High Negotiations Committee, take part in these discussions jointly.
Khalidi added that on Tuesday evening all opposition groups will hold an internal coordination meeting to discuss their common vision.
In an interview with Sputnik earlier on Tuesday, UN Special Envoy for Syria Staffan de Mistura praised opposition groups for making progress in resolving differences and formulating a joint position.