Egyptian pro-government media urged a "yes" vote Sunday, the second day of a nationwide referendum that would allow President Abdel-Fattah el-Sissi to stay in power until 2030.
Critics have blasted the proposed changes as another major step toward an authoritarian government perhaps even more severe than that of former President Hosni Mubarak, who was ousted in a popular uprising in 2011.
The nationwide referendum came amid an unprecedented crackdown on dissent in recent years. El-Sissi's government has arrested thousands of people and rolled back freedoms won eight years ago.
Polls reopened at 9 a.m. (0700 GMT) Sunday. Voting will continue through Monday to allow maximum turnout, which the government hopes will lend the referendum legitimacy.
Yasser Rizq, chairman of the state-owned al-Akhbar daily and a close confidant of el-Sissi, wrote that the referendum is a direct vote on the president, and that he is expecting a high turnout.
"People are taking part to say 'Yes' for el-Sissi to extend his current term until 2024 and allow him to run for another six-year term," Rizq wrote in his Sunday column.
Abdel Mohsen Salama, the chairman of the state-owned al-Ahram media organization, urged people to vote as an "urgent necessity" in the newspaper's Sunday edition.
Opposition voices have largely been shut out amid the rush to hold the referendum. Parliament, packed with el-Sissi supporters, overwhelmingly approved the amendments on Tuesday.
The Civil Democratic Movement, a coalition of liberal and left-leaning parties, urged people to vote "no" to the changes, which would also further enshrine the military's role in politics.
Election officials have not released estimates on voter turnout but say the referendum's results are expected within a week.
Trucks with loudspeakers drove around central Cairo Sunday morning, playing patriotic songs and urging people to vote.
El-Sissi was elected president in 2014, and re-elected last year after all potentially serious challengers were either jailed or pressured to exit the race.