Several Egyptian Islamist parties vowed to boycott a Tuesday meeting that aims to set guidelines for drafting the country's new constitution, dpa reported.
Deputy Prime Minister Ali al-Selmi had invited all parties, political groups and academics to discuss a road map for drafting the charter.
Liberal parties welcomed the meeting, but Islamists led by the Muslim Brotherhood's Freedom and Justice Party rejected the invitation.
The party accused the interim government of "attempting to usurp the powers" of the new parliament.
After the parliamentary elections, set for November 28, a committee will be formed to draft a new constitution ahead of the presidential election.