Initial results of Egypt's presidential elections show that incumbent President Abdel Fattah El-Sisi is securing an overwhelming majority, with a vote share of around 90 percent, Ahram Arabic and state news agency MENA reported.

El-Sisi's sole rival, Ghad Party head Moussa Mostafa Moussa, appears to have obtained a meager 2-3 percent in most parts across the country.

Preliminary results also suggest that an average of 7 percent of electors have invalidated their votes in the overall election.

In Egypt's second city of Alexandria, El-Sisi received around 88 percent of the vote, with a turnout of about 39 percent, Egypt's state news agency MENA said. His rival Moussa gained less than 3 percent of the vote and some 9 percent of voters had invalidated their ballots there.

In Daqahliya, one of the country's most populated governorates, El-Sisi received 85 percent of the vote and Moussa polled just 2 percent, with almost 47 percent of eligible voters casting their ballots, according to Ahram Arabic.

In the Nile Delta governorate of Gharbiya, El-Sisi obtained 90 percent of the vote, with a turnout of more than 50 percent, Egypt's state news agency MENA said.

In Beheira, another governorate with a large population, El-Sisi garnered 87.5 percent of the vote while Moussa obtained 2.5 percent. Around 7 percent of voters there had invalidated their votes.

El-Sisi late on Wednesday expressed pride at Egyptians who had headed to the polls.

"The voice of the Egyptian masses will undoubtedly remain a witness that the will of our nation is imposing itself with a force that knows no weakness," he wrote on Twitter.

"The scenes of Egyptians at polling stations will remain my source of pride and honour and a compelling proof of the greatness of our nation, whose most precious sons have offered [their] blood so that we can move together towards the future," he added.

Hours before polls closed on Wednesday, the country's electoral authority extended the vote by one hour.

There are around 59 million eligible voters in Egypt.

Official results are due on April 2.