The foreign ministry has said initial indicators from Australia and the Gulf states show a high turnout of voters in Egypt's presidential election, with long queues at polling stations.
Egyptians living abroad began casting their ballots on Thursday at embassies and consulates across 124 countries.
Voting will be from 9am to 9pm local time from Thursday until Sunday.
Egyptians must choose between former army chief Abdel-Fattah El-Sisi -- who led the army's ouster of Mohamed Morsi after mass protests against him -- and leftist politician Hamdeen Sabahi.
The vote is the second milestone in a transitional roadmap set out by the interim authorities following Morsi's ouster last July. The first was a January referendum on an amended constitution in which only 107,000 of 600,000 eligible expatriates voted.
The foreign ministry said nearly the same number are allowed to vote in this poll.
"We aim to facilitate procedures in order to increase voter turnout, so people have a real engagement in the country's political life," ambassador and interim Deputy Prime Minister Hamdy Louza told reporters on Wednesday.
Officials say an estimated 6-8 million Egyptians live abroad, with Saudi Arabia housing the largest expat community – almost 45 percent of the total.
Adel Alfy, Egypt's consul in Jeddah, told Al-Ahram newspaper that the consulate had witnessed high turnout of around 700 voters in the first few hours, despite the hot weather. The consulate is providing free transportation to voters living in nearby cities, he added.
Other diplomats in European countries with fewer consulates have expressed worries that a ban on postal voting could reduce turnout.
Postal voting was banned in the January referendum in order to avoid legal challenges, with voters required to cast ballots in person at embassies. The change was cited as one of the factors that contributed to a low turnout abroad.
Whether permanently residing overseas, or temporarily out of the country for any reason, Egyptians are now allowed to cast their votes at embassies and consulates with no prior registration required.
Citing security concerns, officials on Wednesday said voting had been cancelled in some countries, including war-torn Syria, Libya, Somalia and the Central African Republic (CAR).
The official results of expatriate voting will be unveiled along with the domestic vote tally at the end of May.
Meanwhile, Egypt's largest Islamist coalition has urged expats to boycott the presidential vote. It called for a week of peaceful protests against the election, which will take place inside Egypt on 26-27 May.
In a statement released on Thursday under the slogan "Boycott the presidency of bloodshed," the National Alliance to Support Legitimacy (NASL) said the protests are a continuation of revolutionary momentum against the transitional roadmap.
Compared to the constitutional referendum held under deposed Islamist president Morsi, Egyptians came out in larger numbers in January to vote on amendments to the charter.
The Muslim Brotherhood-led coalition insists Mohamed Morsi remains the legitimate president. It describes Morsi – who faces multiple trials on charges including murder and espionage – as the "kidnapped president."
Despite the dwindling number of street protests – now mainly confined to universities – the NASL consistently claims the momentum of demonstrations is unscathed.