Supporters are pouring into Cairo's iconic Tahrir Square as Mohamed Morsi prepared to address a "rebirth" rally on the eve of his swearing-in as Egypt's first civilian president.

Thousands gathered from mid-morning on Friday, braving the searing heat, hours before Morsi was expected to arrive in the huge central plaza that was the epicentre of the protest movement that toppled Hosni Mubarak last year.

Morsi "is taking part in the march of a million Egyptians... at Tahrir Square and across the country", the official news agency MENA cited his spokesman Yasser Ali as saying, adding that he would "make a speech to the great Egyptian people".

Ali said that Morsi will speak about "efforts to launch his programme for the rebirth of Egypt".

The Muslim Brotherhood, the group that Morsi belonged to until he resigned after winning the presidential election, has called for a huge demonstration on Friday in Tahrir Square under the slogan: "Day of the transfer of power".

The presidency announced late on Thursday that Morsi would be sworn-in on Saturday before the constitutional court, after differences with the army over the transfer of power to the nation's first civilian president.

Morsi "will go at 11am (0900 GMT) Saturday to the constitutional court to take the oath before the court's general assembly", said a statement released by MENA.

The president will then go on to Cairo university to celebrate his investiture and make an inauguration speech to the nation, the statement said.

Media reports said Morsi was consulting a cross-section of Egyptian society before appointing a premier and a cabinet mostly made up of technocrats.

Traditionally the president takes the oath in parliament, but Egypt's top court has ordered the disbanding of the Islamist-dominated legislature.

The military subsequently assumed legislative powers and also formed a powerful national security council headed by the president but dominated by generals.

By agreeing to be sworn in by the Constitutional Court, Morsi is effectively acknowledging the court's decision to dissolve parliament.