Syrian National Coalition President Ahmad Jarba said on Sunday the opposition would not attend proposed peace talks in Geneva unless there was a clear timeframe for President Bashar Assad to leave power.

"We have decided not to enter Geneva talks unless it is with dignity, and unless there is a successful transfer of power with a specific timeframe, and without the occupier Iran at the negotiating table," Jarba told an Arab League emergency meeting in Cairo.

Jarba's latest comments throw the proposed talks into further confusion. The United Nations envoy to Syria has said there would be no pre-conditions for the long-delayed peace talks.

The talks are meant to bring Syria's warring sides to the negotiating table, but have been repeatedly delayed because of disputes between world powers, divisions among the opposition and the irreconcilable positions of Assad and the rebels.

Arab and Western officials said this week that international powers were unlikely to meet their goal of holding the conference in November.