An Islamist-led assembly finalized a new constitution early on Friday aimed at transforming Egypt and paving the way for an end to a crisis that erupted when President Mohammed Morsi gave himself sweeping new powers last week.

Morsi said his decree halting court challenges to his decisions, which provoked protests and violence from Egyptians fearing a dictator was emerging 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 said on Thursday night. "There is no place for dictatorship."

The assembly concluded the vote after a session that lasted 19 hours, approving all articles including presidential powers, the status of Islam, the military's role and human rights.

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.

President Morsi is expected to ratify the document by Saturday, allowing a referendum to be held as soon as mid-December.

"We have finished working on Egypt's constitution. We will call the president (on Friday) at a reasonable hour to inform him that the assembly has finished its task and the project of the constitution is completed," said Hossam el-Gheriyani, head of the assembly in a live broadcast of the session.

The vote was often interrupted by bickering between the mostly Islamist members and Gheriyani over the document's 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", added Gheriyani, after which Egypt's national anthem was played.

Gheriyani said the assembly would continue its work in an administrative capacity to prepare for the popular referendum that Morsi is to call for after reading the finalized draft.

Morsi's 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 June elections, and its allies.

Two people have been killed and hundreds injured in the protests since the decree on Nov 22.

Setting the stage for more tension, the Muslim Brotherhood and its 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, where a sit-in by the president's opponents entered an eighth day on Friday.

Seeking to calm protesters, Morsi said he welcomed opposition but it should not divide Egyptians and there was no place for violence. "I am very happy that Egypt has real political opposition," he said.