Army chief Abdel Fattah al-Sisi laid out the details on Wednesday of a roadmap for Egypt after the ouster of president Mohamed Morsi which names the head of the Supreme Constitutional Court the country's caretaker leader.

Sisi, the defence minister in Morsi's government, also announced a freezing of the Islamist-drafted constitution and early presidential elections.

He did not say how long the transition period would last and insisted the armed forces would "remain far away from politics".

The announcement came in a televised address to the nation.

Sisi was joined by the country's top clerics, Sunni Muslim Grand Imam Ahmed al-Tayyeb and Coptic Christian Pope Tawadros II, as well as opposition chief Mohamed ElBaradei.

Also present at the meeting were representatives of the Tamarod campaign, which launched the massive anti-Morsi protests, and the head of the Salafist Al-Nur party, Yunis Makhyun.

"The head of the Supreme Constitutional Court will take the oath before the court's general assembly," Sisi said, without specifying a date.

"Early presidential elections will be held and the head of the Supreme Constitutional Court will manage the affairs of the state during the transitional phase until the new presidential elections," he said.

He said the head of the SCC, Adly Mansour, would have the "authority to issue constitutional decrees during the transitional phase."

A "strong technocratic government" with "full powers" will be formed, Sisi said.

He said a panel, "including all trends," would be formed to look into amending the constitution, calling on the SCC to quickly draft a bill regulating parliamentary elections and to begin preparations for the elections.

After the announcement, Morsi denounced the move as "illegal" and urged Egyptians to "peacefully resist the coup as he himself will do", a senior aide told AFP.

Opposition leader Mohamed ElBaradei said the roadmap announced by Sisi "meets the people's demands for early presidential elections".

The army's dramatic move came after millions of Egyptians took to the streets to call for Morsi's ouster, accusing him of betraying the 2011 revolution that brought him to power.

Egypt has been deeply polarised, with divisions between Morsi's mainly Islamist supporters and a broad-based opposition sometimes spilling into the streets in deadly violence.

Sisi said a commission "of credible figures" would be formed to begin a process of national reconciliation.