Ex-president Rafael Correa returned to Ecuador from Belgium on Friday to lead the campaign against a referendum called by the government effectively to prevent his re-election.

Videos posted on Twitter showed an ebullient Correa addressing cheering supporters from atop an open truck at the head of a cavalcade of vehicles shortly after his arrival in the southwestern port city of Guayaquil.

Correa is locked in a battle with his successor Lenin Moreno for control of their deeply divided leftist ruling Country Alliance party.

"They said he would not come back. They said he was afraid to return. The New History of Ecuador begins here. Here are the real people. Your people!" posted lawmaker Carlos Viteri, who accompanied Correa.

The ex-president wants "professional imposter" Moreno ousted from the party, accusing him of governing with the opposition and breaking with the party's leftist program.

Since his election last year, Moreno has steadily dismantled Correa's populist leftist legacy and made overtures to the business community and the political right.

Correa, who preceded Moreno in office, retired to his wife's native Belgium only to return initially in late November to battle Moreno for control of the party, which is split between the two men.

"He is coming to give a push to the 'No' campaign in a consultation that is unconstitutional, illegal and illegitimate," the head of the party's Correa wing Ricardo Patino told AFP.

Correa ally vice president Jorge Glas was jailed last month for six years for graft after being found guilty of receiving $13.5 million dollars in kickbacks from Brazilian construction giant Odebrecht.

Correa had maintained during the case that Glas was a "political prisoner" and that there was no evidence against him. He claimed the conviction was nothing more than a way for Moreno to strengthen his hand and seize control of the vice president's office.

The ex-president has refused to rule out running in the 2021 presidential election to avenge what he has called the "betrayal" by his former supporter Moreno.

Supporters say he plans to remain in the country at least until the February 4 referendum, in which Moreno is backing a "yes" vote that would, among other questions, reintroduce term limits to prevent presidents from running indefinitely.