CAIRO - Egypt extended voting into a third day Wednesday in a presidential election seen as a plebiscite on the former army chief, after turnout fell below that in the poll won by the Islamist leader he ousted.

The move raised further question marks about the democratic credentials of an election already marred by a deadly crackdown on the main opposition since last year.

Electoral officials said over the scheduled two days of polling Monday and Tuesday just 37 per cent of eligible voters cast their ballot - well below the nearly 52 per cent who voted in the 2012 election that brought president Mohamed Morsi to power.

The low turnout came despite a personal appeal from retired field marshal Abdel Fattah al-Sis.

His victory over his sole rival, leftist leader Hamdeen Sabbahi, was never in doubt, had urged “40, 45 (million) or even more” of Egypt’s 53 million eligible voters to turn out to give credibility to an election boycotted not only by Morsi’s Muslim Brotherhood but also by influential secular groups.

After reports of a meagre numbers at polling stations on the first day of voting Monday, Sisi’s backers in the state-run media harangued people to go out and vote.

An electoral official said polling had been extended to “give a chance to the largest possible number of voters to cast their ballots.”

On Wednesday, several Cairo polling stations visited by AFP were deserted in the initial hours of voting.

“They didn’t get enough votes, so they extended polling into a third day,” complained filmmaker Mohamed Ali Hagar, who said he would stay away regardless.

“All elections in this country are rigged.”

The extension of polling hours in a bid to boost turnout did little to raise the credibility of the vote in the eyes of Western governments whose longstanding alliance with Cairo was seriously compromised by last year’s overthrow of the elected president.

“The regime had projected Sisi in a certain way, but that facade has been undermined... support for Sisi was overstated,” said Shadi Hamid, of the Brookings Institution’s Saban Centre.

“Nobody outside Egypt or in the West was under illusion that this was a free and fair election... It makes the regime look incompetent and transparently cynical,” he told AFP.

Sabbahi slammed the extension, saying it raised “questions... about the integrity of the process”.

His campaign team announced it was withdrawing its observers from polling stations.

Sisi’s campaign team too filed a complaint against the extension, suggesting an extra day of polling might be a burden on voters.

“We had hoped the commission would extend voting each day after 9:00 pm because it is very hot,” Sisi’s spokeswoman Mona el-Kouedi told AFP.

“But we think an extra day would be an exertion for voters, and the judges (overseeing the vote) would get tired.”

Morsi’s Muslim Brotherhood, which had championed a boycott of the election, hailed the low turnout.

“The great Egyptian people have given a new slap to the military coup’s roadmap and ... written the death certificate of the military coup,” the Brotherhood’s political arm, the Freedom and Justice Party, said.

The Brotherhood has been subjected to a massive crackdown in which hundreds of its supporters have been killed and was designated a terrorist organisation last December.

All of the movement’s main leaders are now in jail or exile and Morsi himself is on trial on charges that could carry the death penalty.

Several key activists behind the Arab Spring uprising that ousted long-time strongman Hosni Mubarak in 2011 had also called for a boycott charging that Sisi was a new autocrat in the making.

Sisi’s ouster of Morsi on July 3 triggered the worst peacetime bloodshed in Egypt’s recent history, but the former army chief has vowed to stamp out the violence.

He has said “true democracy” in the Arab world’s most populous nation will take a couple of decades.

A big security force deployment prevented any major polling day incidents.

But in the restive Sinai Peninsula, where Egypt’s deadliest militant group has its base, gunmen killed a soldier near the Gaza border on Wednesday, security officials said.