More than 200 diplomats have said they will not supervise expatriate referendum voting on the draft constitution, which is scheduled to begin Saturday.
Egyptians abroad are supposed to be able to cast ballots for four days in 137 embassies and 11 consulates.
The referendum vote in Egypt is scheduled for 15 December.
Diplomatic officials are boycotting the referendum to remain politically neutral, one diplomat said, and made the joint decision after protesters died Wednesday night in Cairo.
Competing protests of the president's supporters and opponents broke out in violence Wednesday night, injuring hundreds. In recent weeks, President Mohamed Morsy has sparked the unrest by speeding the constitution's completion and issuing a decree expanding his own powers.
"We, the undersigned members of the diplomatic and consular corps, serve our homeland in complete impartiality and without bias to achieve and uphold its interests in the positions of responsibility we assume," read a statement signed by 204 diplomats. "To be consistent with our principles and our loyalty to our country, we denounce each sinful hand that participated directly or indirectly in the bloody events that took place Wednesday and we announce our rejection of the Foreign Ministry's supervision over the constitution draft referendum of expatriate Egyptians because the blood of Egyptians is being shed."
The Egyptian ambassadors to Australia, Finland, Spain and Sri Lanka were among those who signed the statement issued Thursday.
Diplomatic officials also recently expressed discontent about what they said was a political directive from the government urging them to support President Mohamed Morsy's constitutional declaration.
Last year, 245 ambassadors and other consular representatives issued a statement calling on the then-ruling Supreme Council of the Armed Forces to hand over power to civilians.
Despite the most recent declaration, preparations are continuing as normal for voting abroad, according to Assistant Foreign Minister for Consular Affairs Ali al-Ashry. Embassies and consulates will open the voting process on Saturday from 8 am to 8 pm, he said in a statement Thursday. Voting will continue until Tuesday, 11 December, by direct ballot or mail.
The ministry has sent additional representatives to Gulf states, where high turnout is anticipated.
Edited translation from Al-Masry Al-Youm
