Egypt's interim president will likely appoint centre-left business lawyer Ziad Bahaa Eldin as prime minister within 24 hours, a presidential aide told AFP on Sunday.

The president, Adly Mansour, was also leaning towards picking Nobel Laureate Mohamed ElBaradei as vice president, after Islamists objected to an initial proposal to appoint ElBaradei as prime minister.

"The president is leaning towards appointing Bahaa Eldin and ElBaradei," Mansour's media advisor Ahmed al-Muslimani told AFP.

He said a final decision would be announced "tomorrow".

If confirmed, Mansour has gone for a technocrat without the baggage of ElBaradei, whose candidacy outraged Salafi Islamists in a loose coalition that backed president Mohamed Morsi's overthrow by the military on Wednesday.

The Salafis say ElBaradei, viewed as an ardent secularist and top opponent to Islamist Morsi, would have been a divisive premier.

The son of a prominent writer, Bahaa Eldin would be handed the enormous task of bringing a semblance of unity to the new Egypt four days after the military ousted Morsi.

Eldin has a long and distinguished career as a business lawyer.

He has worked for a string of law firms, including in Washington, before becoming an adviser to the Egyptian economics ministry in 1997.

The father of two boys entered politics in 2011 after the 2011 Arab Spring-inspired revolution that toppled longtime autocratic president Hosni Mubarak.

News of his likely appointment follows a day of confusion about who will serve as interim prime minister, after the Salafist Al-Nour party said the job should not be given to former UN watchdog chief ElBaradei.