The announcement by the election committee head Ismail Hamdi to delay early voting on the charter came as a surprise, and it was difficult to predict whether it will lead to a breakthrough in the political crisis.
The president's aides said the move would ease some pressure and would provide room for negotiations with the opposition.
But Morsi's opponents have rejected talks, saying he must first cancel the referendum and meet other demands. Late Friday, an opposition umbrella group called for an open-ended sit-in in front of the presidential palace.
The crisis began Nov. 22, when Morsi issued a decree that gave him absolute powers and immunity from judicial oversight. It deepened when he called for a Dec. 15 national referendum on the draft constitution hurriedly produced by the Islamist-led constituent assembly. The draft was infused with articles that liberals fear would pave the way for Islamizing Egypt.
Legal Affairs Minister Mohammed Mahsoub said the administration was weighing several proposals - including calling off the referendum and returning it to the constituent assembly for changes. Another possibility was disbanding the constituent assembly and forming a new one, either by direct vote or an agreement among the political forces.
"We have a big chance tomorrow," Mahsoub told the Qatari-based Al-Jazeera network, referring to what he said was a meeting between Morsi and political forces. "There are no deadlines or referendums outside the country. Tomorrow or day after, we might reach a good agreement."
Vice President Mahmoud Mekki also told the broadcaster that he had contacted leading democracy advocate Mohamed ElBaradei to join Morsi in a dialogue. ElBaradei leads the newly formed National Salvation Front, a group of liberals and youths who opposed Morsi's decrees and led the protests in Cairo.