Pre-election polls indicate that there is strong support for the reforms the president is seeking.
According to a poll conducted by Market, a private frim, Correa’s party would win 65 to 68 assembly seats compared to 38 for the opposition.
The survey has a margin of error of three percentage points.
However, another survey conducted by Cedatos-Gallup showed that 36 per cent of would-be voters remain undecided.
More than nine million Ecuadoreans from the Andean hamlets to the Amazon jungle will choose from among more than 3,000 candidates on Sunday, including former beauty queens and Marxists.
Many voters are confused by the myriad candidates and their pledges, as well as complex proportional method for assigning seats that could delay Sunday's official tally.
Correa, a US and European-educated former finance minister, says that the 130-seat constituent assembly will stem political instability in the country despite warnings his economic reforms could scare off foreign investors.
Critics claim Correa is following in the footsteps of Hugo Chavez, the president of Venezuela, who in 1999 had successfully pushed for the election of a constituent assembly filled with his supporters.
They claim that, like Chavez, Correa would use the constituent assembly to concentrate power in his own hands.
Alvaro Noboa, Ecuador's wealthiest man, and one of the 3,229 candidates running for assembly elections, has vowed to defeat what he says are the power ambitions of Correa, whom he calls "the communist devil".
Noboa said during his electoral rally: "Correa has become a tyrant who maintains you in poverty, the tyrant who keeps you sick, the tyrant who keeps you without a home or health care. But I am here, Ecuadorans."
Ana Maria Correa, a political analyst based in the capital Quito, and of no relation to the president, said Correa's government "has a certain moral superiority, the idea that they are finally heading a revolution that has been proposed for more than 30 years."
"At times, this revolutionary logic is leaving procedures, rules, the law by the wayside."