Posters calling on people to join the protests against Morsi’s rule have sprung up around Cairo, plastered on walls and stuck on car windows along with "June 30" graffiti daubed along streets, AFP reported.
The week leading up to the showdown has already seen eight people killed, including an American, and scores more injured as protesters from both sides took to the streets.
Morsi, a senior Muslim Brotherhood leader, is Egypt's first president elected in a free vote, catapulted to power by the 2011 uprising that ended three decades of dictatorial rule.
His opponents, who have been massing outside the presidential palace and in Cairo's Tahrir Square, accuse Morsi of betraying the revolution by concentrating power in the ruling party’s hands.
In the run-up to the anti-Morsi rallies, thousands of his supporters gathered in Cairo's Nasr City neighborhoods to listen to fiery speeches urging them to defend the president's legitimacy.
Morsi's Freedom and Justice Party, the political arm of the Muslim Brotherhood, called for a "general mobilization" in support of the president who has said he wants to stay the course until the end of his term in June 2016.
But leading opposition figure, Nobel laureate Mohamed ElBaradei, urged the president "to listen to the people" and step aside.
The fervent displays of emotion from both camps highlight the deep divisions in the Arab world's most populous country.
The army, which led a tumultuous transition after the revolution that ousted dictator Hosni Mubarak, has warned it will intervene if there is major unrest.
Since taking office, Morsi has battled with the judiciary, the media and the police. The economy has taken a tumble, investment has dried up, inflation soared and the vital tourism industry has been battered.
Egyptians have been stocking up on food and withdrawing cash in anticipation of Sunday's rallies and, adding to the tension, fuel shortages have caused very long queues outside petrol stations, bringing some parts of the capital to a standstill.
On Saturday at least eight deputies also resigned from the Shura Council in support of the people.