Around 64,000 expatriates have voted in the constitution referendum – ten percent of those eligible - with just one day left, the election committee announced on Saturday.
About 2.7 million Egyptians live abroad, according to the International Organisation for Migration, but other estimates put the figure at as many as 7-8 million.
A referendum at home is scheduled for 14-15 January.
The voting process for expats, which is being monitored by a foreign ministry panel, was mostly going ahead smoothly, with minimal reported attempts to hinder the vote, the panel added.
Expats won the right to cast votes in elections at Egyptian embassies and consulates following the January 2011 uprising.
The number of Egyptian expats who are eligible to vote is 681,346 across 161 countries, with Saudi Arabia hosting the highest number – around 45 percent of the total.
Voting for expats started on 8 January and is due to end on Sunday 12 January.
The referendum is the first landmark in a transition roadmap drawn up after the army overthrew Islamist president Mohamed Morsi in July amid massive protests against his year-long rule.
Parliamentary and presidential elections are scheduled to follow by mid-2014.
The 2012 Islamist-drafted constitution was suspended following Morsi's ouster in July 2013.
Around 40 percent of registered expats voted in the 2012 constitution referendum, with more than 63 percent voting in favour of the charter.
The Muslim Brotherhood and its supporting National Alliance to Support Legitimacy are calling on Egyptians to boycott the 2014 referendum.