Hardliners in his camp are determined to implement provisions for stricter rule by Islamic law in the charter, which is likely to further fuel divisions.
Morsi's liberal and secular opposition now faces the task of trying to organise the significant portion of the population angered by what it sees as attempts by Morsi and the Brotherhood to gain a lock on political power.
The main opposition group, the National Salvation Front, said it would now start rallying for elections for the legislative, Lower House of Parliament, expected early next year.
The new constitution would come into effect once official results are announced, expected in several days. When they are, Morsi is expected to call for the election of the lower chamber no more than two months later.
In a sign of disarray in Morsi's Administration, his vice-president and possibly the central bank governor resigned during yesterday's voting.
Vice-President Mahmoud Mekki's resignation had been expected since his post is eliminated under the new constitution. But its hasty submission even before the charter has been sealed and his own resignation statement suggested it was linked to Morsi's policies.
"I have realised a while ago that the nature of politics don't suit my professional background as a judge," his resignation letter, read on state TV, said. Mekki said he had first submitted his resignation last month but events forced him to stay on.
The status of Central Bank Governor Farouq el-Oqdah was murkier.
State television first reported his resignation, then soon after reported the Cabinet denied he has stepped down in a possible sign of confusion.
El-Oqdah, in his post since 2003, has reportedly been seeking to step down but the Administration was trying to convince him to stay on.
The confusion over el-Oqdah's status comes at a time when the government is eager to show some stability in the economy as the Egyptian pound has been sliding and a much-needed US$4.8 billion loan from the IMF has been postponed.
Over the past month, seven of Morsi's 17 top advisers and the one Christian among his top four aides resigned. Like Mekki, they said they had never been consulted in advance on any of the President's moves, including his November 22 decrees, since rescinded, that granted himself near absolute powers.
Yesterday's voting
17 of Egypt's 27 provinces
2nd and final round of the referendum
71.4 per cent of those who voted yesterday said "yes", according to Muslim Brotherhood tally
30 per cent turnout
First round
56 per cent said "yes" to the charter
32 per cent turnout
Overall
63 per cent approved the referendum
-AP