Egyptian President Mohamed Morsi is facing widespread opposition to a decree last month that gave him sweeping powers. His supporters said the move was necessary to push a new constitution forward, though critics said the post-revolutionary political system is being hijacked by the Muslim Brotherhood.
Morsi, the candidate from the Muslim Brotherhood's Freedom and Justice Party, in June became the first Egyptian president elected in a democratic vote.
Egyptian Vice President Mahmoud Mekki said Wednesday a referendum on the constitution would go ahead Dec. 15.
"We need to reply to the people, the main source of authority, not to political camps and their ability to mobilize in the streets," he was quoted by Egyptian news agency al-Ahram as saying.
Morsi this week left the presidential palace briefly amid widespread protests there. FJP officials told al-Ahram on background the Islamist movement intended to "stay the course" despite mounting opposition.
Some articles related to a woman's role in society and to Islamic law were criticized.
The Muslim Brotherhood said it was planning its own demonstrations to counter the growing chorus of frustration targeting Morsi.