Egypt's security chief has warned supporters of the ousted president, Mohamed Morsi, that troops will use unprecedented force against anyone attempting to disrupt voting on a new referendum.
"I am telling them, they will be faced with force, decisiveness and strength never seen before," interior minister Mohammed Ibrahim said on state TV on Monday. "Everyone rest assured, we are watching your back."
Authorities consider the draft charter to be a milestone in a military-backed transitional road map put in place after Morsi was overthrown in a popularly backed military coup last July.
State television showed Ibrahim on Monday inspecting some of the 350,000 police and army personnel, including special forces and paratroopers backed by armored vehicles and helicopters, currently being deployed to streets across the country to secure the polls and encourage a high turnout.
Hundreds of Egyptians have been killed by security forces while protesting against the removal of Morsi.
The January 14-15 vote provides the country's increasingly popular military chief, General Abdel Fattah el-Sisi, with a first electoral test since he ousted Morsi.
A comfortable "yes" vote and a respectable turnout would be seen as bestowing legitimacy, while undermining the Islamists' argument that Morsi remains the nation's elected president.
Morsi's Muslim Brotherhood, which fell from power and is now branded a terrorist group, has called for a boycott of the vote.
In its latest statement, a Brotherhood-led alliance said: "The blood of Egyptians is not a ladder to take over the seat of the kidnapped president."
Regarding whether to vote "yes" or "no" on the document, it added: "The boycott is the only way."
Morsi faces trial on several charges, including inciting killing of protesters, conspiring with foreign groups and orchestrating jailbreaks during 2011 uprising which forced his predecessor Hosni Mubarak from power.
"Topple the blood-stained constitution with civilised, peaceful masses," it said, urging its supporters not to hold demonstrations near polling stations.
The charter had been drafted in 2012 by an Islamist-dominated panel under Morsi, but was suspended after his removal and heavily amended by two panels dominated by secular-minded politicians and legal experts under the interim government.
While limiting the role of Islamic law in legislation, the charter consolidates military privileges such as the ability to try civilians in front of military tribunals in specific conditions.
Many of its articles appear progressive compared to the text drafted under Morsi.
Seven Egyptians were arrested on Monday after they were found hanging posters calling for Egypt to cast a "no" vote to reject the new constitution.
The New-York based Human Rights Watch said: "Egyptian citizens should be free to vote for or against the new constitution, not fear arrest for simply campaigning for a 'no' vote.
"Protecting the right to vote requires safeguarding the right to free expression."