President Hosni Mubarak hailed the March 26 referendum as a "free expression of the people's will," and vowed to continue the course of political reform in the country.
"The people are the real winners in this referendum," he said.
He said the amendments are designed to strengthen the role of parliament and political parties, improve election monitoring, and combat terrorism, among other things.
Mubarak said that with a turnout of 27.1%, 75.9% voted in favor of the amendments.
But a number of opposition parties and human rights groups have already challenged the figures, with independent monitors saying turnout at some polling stations was a mere 3-5%.
The Muslim Brotherhood opposition bloc said the actual turnout was under 10%.
The conflict between the authorities and the opposition, which boycotted the referendum, centers on amendments to Articles 179 and 88 of the Constitution, which, in particular, authorize the security services to monitor telephone calls, conduct searches and make arrests without judicial oversight.
Another amendment bans political parties based on religion.
The opposition also said the amendments will weaken judicial checks on elections and strengthen the president's security clout at the expense of civil rights.
The Egyptian Organization for Human Rights said the government had forced public-sector workers to go to polling stations.
In several districts, public employees were bused in to cast ballots.
