Egyptians will head to the polls on March 26-28 in the first round of a presidential election, National Elections Authority chief Lasheen Ibrahim said on Monday.

A second round will be held on April 24-26 if required, he told a news conference in Cairo.

Ibrahim said the commission would accept applications from presidential hopefuls between January 20 and 29.

"The provisional list of candidates and the numbers of their supporters will be published" in state-run newspapers Al-Ahram and Al-Akhbar on January 31, he said.

Once any appeals by rejected candidates are settled, "the final list of candidate names and their symbols will be announced and published in the official gazette and Al-Ahram and Al-Akhbar newspapers" on February 24, he said.

That will mark the official start of the campaign, which will run until March 23, Ibrahim said, with final results to be announced on May 1.

Egyptians living abroad can vote between March 16 and 18, he added, with second round ballots on April 19-21 if necessary.

Incumbent Abdel Fattah al-Sisi is widely expected to stand for re-election and win in the first round.

The former army chief was elected in 2014, a year after leading the military to oust his predecessor Mohamed Morsi amid mass protests against the Islamist's year-long rule.

On Sunday, former premier Ahmed Shafiq, once seen as a main challenger to Sisi, said that he would not be a candidate, reversing a previous pledge to stand.

Shafiq was appointed premier by Hosni Mubarak shortly before he was toppled from the presidency in the 2011 uprising, and only narrowly lost out in the 2012 election to Morsi.

- Years of turmoil -

After years of political, security and economic turmoil since Mubarak's ouster, many Egyptians might have voted for Shafiq, nostalgic for a continuation of Mubarak's rule, analysts believe.

Other potential candidates include Khaled Ali, a rights lawyer and 2012 presidential candidate who challenged the government over Red Sea islands Egypt gave to Saudi Arabia.

In November, Ali announced his intention to stand again in 2018.

However, he had been sentenced in September in absentia to three months in jail on accusations of "offending public decency", a ruling he appealed.

The sentence was over a photograph Ali says was fabricated and that appeared to show him making an obscene gesture while celebrating a court ruling in the case of the islands' transfer.

Ali has said only the committee organising the election can decide whether that ruling would disqualify him as a candidate.

Another hopeful, colonel Ahmed Konsowa, was given six years in prison in December by a military court after the previous month announcing his intention to stand.

Konsowa's lawyer said his client was given the sentence for stating political opinions while still a serving officer, even though Konsowa said he had been trying to resign from the military for more than three years.

Lawyer Asaad Heikal said Konsowa had only followed Sisi's example in announcing his candidacy. Sisi was in uniform when he did so, before later resigning as defence minister.