Ecuadorians on Sunday resoundingly approved a new constitution that would significantly expand leftist President Rafael Correa's powers and allow him to run for two more consecutive terms, unofficial partial results showed.

Voters gave the measure 63-per-cent backing, according to a nationwide quick count by an independent citizen's group.

"We're making history! Onward!" a jubilant Correa proclaimed in his coastal hometown of Guyaquil after his crushing victory became clear. "This is a confirmation of the citizens' revolution we're offering."

The unofficial results represented four per cent of the vote and were compiled by the independent group Citizen's Participation, which conducted a nationwide sample with a margin of error of plus or minus half a percentage point.

According to the quick count, 29 per cent of Ecuadorians voted "no" while seven per cent voted "null" — neither yes nor no — and one per cent turned in blank ballots.

Exit polls from Sunday's referendum show the new constitution winning with at least 66 per cent of the vote.

Sunday's victory was the third nationwide electoral victory for Correa since he won office in November 2006 with 57 per cent of the vote. He also won the referendum approving the rewriting of a new constitution.

The new constitution will almost certainly lead to presidential, congressional and local elections early next year, and an overhaul of the judiciary in which Correa is expected to play a decisive role.

The Central Bank and other key institutions also would cede or lose autonomy to Correa, this chronically unstable nation's sixth president in a decade.

That should help the U.S.- and European-trained economist, who presides over of South America's fifth-largest oil producer, fashion what he has called a "new model society."

Other clauses in the new charter upset social conservatives, such as one that recognizes the family "in its diverse types."

And while the charter holds that life "begins with conception," it also guarantees "the right to freely make responsible and informed decisions about one's health and reproductive life."

The Roman Catholic hierarchy of this overwhelmingly Catholic nation complains that those provisions could lead to legal abortion and same-sex unions.