The latest opinion polls give Lucio Gutierrez, a 45-year-old retired army colonel and former coup leader, a healthy lead of at least 15 percentage points over banana tycoon Alvaro Noboa.

I feel like a winner

Lucio Gutierrez

The vitriolic character of the run-off between two populist outsiders at either end of the political spectrum continued until the close of the campaign, with Mr Noboa declaring he had been "deceived" by not being able to face his opponent in a television debate.

Both candidates held the final night of rallies in Guayaquil, Ecuador's largest city with two million inhabitants.

Mr Gutierrez pressed home again a familiar theme of the campaign, promising "to fight against corruption, which has caused so much damage and has mired the Ecuadorian people in poverty".

Noboa has tried to trade on fears of social unrest

Both candidates have highlighted the problem of corruption in a country where embezzlement is estimated at $2bn per year - or a fifth of national debt.

Mr Gutierrez is seen as a champion of the country's four million Indians - whom he helped overthrow President Jamil Mahuad in 2000.

Mr Noboa, the country's richest man, has in an attempt to narrow the gap between candidates, raised the spectre of social unrest if Mr Gutierrez wins.

"When the people ask him [Mr Gutierrez] for jobs, housing and subsidies for the poor, he will turn into a dictator and riddle you with bullets, bullets, bullets," he said in a TV interview.

Stop and give up your candidacy... rather than go through the shame of being defeated at the ballot box

Alvaro Noboa

The new president will take over in January from Gustavo Noboa - no relation to Alvaro Noboa - who decided not to stand.

About 140 observers from the European Union, Organisation of American States and the Andean Parliament said the electoral campaign had been free from fraud.