Morsi said law decree halting court challenges to his decisions, which provoked demonstrations and violence from Egyptians fearing a new dictatorship less than two years after they ousted Hosni Mubarak, was "for an exceptional stage."
"It will end as soon as the people vote on a constitution," he told state television while the constituent assembly was still voting on the draft. "There is no place for dictatorship."
The opposition cried foul. Liberals, leftists, Christians, more moderate Muslims and others had withdrawn from the assembly, saying their voices were not being heard. They have called for big rally on Friday, an eighth day of protests.
Protesters said they would push for a 'no' vote in a referendum, which could happen as early as mid-December. If approved, it would immediately cancel the president's decree.
"We fundamentally reject the referendum and constituent assembly because the assembly does not represent all sections of society," said Sayed el-Erian, 43, a protester in Cairo's Tahrir Square. He is a member of the liberal Dostour (Constitution) Party, set up by prominent opposition figure Mohamed ElBaradei.
The plebiscite is a gamble based on the Islamists' belief that they can mobilise voters again after winning all elections held since Mubarak was overthrown in February 2011.
But it will need the cooperation of judges to oversee the vote, though many were angered by Morsi's decree that they said undermined the judiciary. Some judges have gone on strike.
The assembly concluded the vote after a 19-hour session, approving all 234 articles including presidential powers, the status of Islam, the military's role and the extent to which human rights will be respected in the post-Hosni Mubarak era.
The final draft contains historic changes to Egypt's system of government. It limits to eight years the amount of time a president can serve, for example. Mubarak was in power for three decades. It also introduces a degree of oversight over the military establishment - though not enough for critics.
Morsi is expected to ratify the document by Saturday, allowing a referendum to be held as soon as mid-December on a text the Islamists say reflects Egypt's new freedoms.
"We have finished working on Egypt's constitution," said Hossam el-Gheriyani, head of the assembly in a live broadcast of the session. "We will call the president today (Friday) at a reasonable hour to inform him that the assembly has finished its task and the project of the constitution is completed."
The vote was often interrupted by bickering between the mostly Islamist members and Gheriyani over the articles. Several articles were amended on the spot before they were voted on.
"This is a revolutionary constitution," Gheriyani said, asking members of the assembly to launch a cross-country campaign to "explain to our nation its constitution."
Critics argue it is an attempt to rush through a draft they say has been hijacked by the Muslim Brotherhood, which backed Morsi for president in a June election, and its allies.
Two people have been killed and hundreds injured in the protests since last Thursday's decree, which deepened the divide between the newly empowered Islamists and their opponents.
Setting the stage for more tension, the Muslim Brotherhood and its Islamist allies have called for pro-Morsi rallies on Saturday. But officials from the Brotherhood's party changed the venue and said they would avoid Tahrir Square.
Seeking to calm protesters, Morsi said he welcomed opposition but there was no place for violence. "I am very happy that Egypt has real political opposition," he said.
He said Egypt needed to attract investors and tourists. The crisis threatens to derail early signs of an economic recovery after two years of turmoil. Egypt's benchmark stock index fell on Thursday to a four-month low.
An alliance of opposition groups pledged to keep up protests and said broader civil disobedience was possible to fight what it described as an attempt to "kidnap Egypt from its people."
Eleven newspapers plan not to publish on Tuesday to protest Morsi's decree, one reported. Al-Masry Al-Youm, one of Egypt's most widely read dailies, also said three privately owned satellite channels would not broadcast on Wednesday in protest.
The Brotherhood argues that approval of the constitution in a referendum would bury all arguments about both the legality of the assembly and the text it has written in the last six months.
If Egyptians approve the constitution, legislative powers pass straight from Morsi to the upper house of parliament, in line with an article in the constitution, assembly members said.
The draft injects new Islamic references into Egypt's system of government but keeps in place an article defining "the principles of sharia" as the main source of legislation - the same phrase found in the previous constitution.
It caps the amount of time a president can serve at two terms, or eight years. Mubarak ruled for three decades. It also introduces a measure of civilian oversight - not nearly enough for the critics - over the military establishment.
The president can declare war with parliament's approval, but only after consulting a national defence council with a heavy military and security membership. That was not in the old constitution, used when Egypt was ruled by ex-military men.
Activists highlighted other flaws such as worrying articles pertaining to the rights of women and freedom of speech.
"There are some good pro-freedoms articles, but there are also catastrophic articles like one that prevents insults. This could be used against journalists criticising the president or state officials," said human rights activist Gamal Eid.
A new parliamentary election cannot happen until the constitution is passed. Egypt has been without an elected legislature since the Islamist-dominated lower house was dissolved in June, based on a court order.
"The secular forces and the church and the judges are not happy with the constitution; the journalists are not happy, so I think this will increase tensions in the country," said Mustapha Kamal Al-Sayyid, a Cairo University political science professor.