Nearly 51 million voters will participate in the two-stage vote over the Islamist draft constitution that may seal the fate of the deeply polarised nation.
Clashes erupted between opponents and supporters of the referendum on the draft constitution outside Al-Qaed Ibrahim Mosque in Alexandria after the Friday prayers in which the preacher expressed support for the constitution.
The clashes broke out with demonstrators on both sides throwing stones and deteriorated to street fights leaving 17 injured.
Hundreds of anti-constitution protesters had gathered earlier outside the mosque.
'The people want to bring down the regime', 'Down with the rule of the supreme guide', chanted protesters referring to Brotherhood leader Mohamed Badie.
"The Constituent Assembly is void, and the constitution is sectarian," read the banners as protesters distributed leaflets that rejected the constitution draft, saying such a constitution after the revolution was a "disaster."
Alexandria is among the 10 governorates, where the first stage of public vote will take place tomorrow. The other are Cairo, Daqahlia, Sharqiya, Assiut, Sohag, Aswan, Gharbiya, North Sinai and South Sinai, state-run MENA news agency said.
While the second stage, to take place on December 22, will be held in the remaining 17 governorates.
The National Salvation Front of opposition groups organised demonstrations at the presidential palace and in Cairo's iconic Tahrir Square today, after deciding to call on followers to vote "no" in the referendum, rather than a boycott.
In Tahrir Square, protesters chanted, "Oh martyr we swear by your blood, another revolution anew," and "The people demand the fall of the regime". (MORE)