The conference has been announced by Syrian National Council leader Abdulbaset Sieda as aiming at restructuring the Syrian opposition bloc and creating a Syrian transitional government through talks with other opponents of President Bashar al-Assad.
Western and Arab countries have repeatedly called for better cooperation among those trying to dislodge Assad.
The Syrian National Council was formed in Istanbul last year as an umbrella organization to guide a democratic transition if Assad fell, but has been accused by some of being dominated by Islamists.
Political groups within the SNC have often been at odds with each other, and have not always agreed with other political opposition movements operating within Syria.
Voice of Russia, Guardian, Reuters