Approximately 103,000 expatriates voted in the constitution referendum – significantly fewer than in 2012, the electoral committee told reporters on Monday.
Around 244,000 ballots were cast in the referendum on the Islamist-drafted constitution in 2012.
The scrapping of postal voting contributed to the fall, foreign ministry spokesperson Badr Abdel-Atti told Ahram Online.
The number of those who voted in person this year (103,000) was higher than in the 2012 poll (92-93,000), Abdel-Atti noted.
681,346 Egyptian living in 161 countries, of whom 45 percent live in Saudi Arabia, were eligible to vote.
The largest turnouts were in the US, Saudi Arabia, Kuwait and the UAE.
Postal voting was banned in the referendum, which took place between 8 and 12 January, in order to avoid legal challenges, with voters required to cast ballots in person at embassies.
Around 40 percent of registered expats voted in the 2012 poll, as opposed to 15 percent in this year's vote.
Postal voting accounted for 62 percent (151,000) of the 244,000 ballots cast by expatriates in 2012, with some 92-93,000 voting in person, according to the spokesperson.
Many Egyptian expats lack official documents, which also contributed to the low turnout, the spokesperson added, as did a boycott by supporters of deposed president Morsi's Muslim Brotherhood.
The 2012 Islamist-drafted constitution was suspended following Morsi's ouster in July 2013.
A referendum at home is scheduled for 14-15 January.
Remaining tallies of expat votes are yet to be received and official figures will be announced after the home vote ends, the electoral committee said.