Quito - Ecuador is expected to re-elect left-wing populist Rafael Correa as president Sunday amid complaints from his seven weakened challengers that public money is being misused to finance the incumbent's campaign.

Correa, 46, looked poised to secure victory in the first round without a runoff. The election is already historic in Ecuador as the first in which an incumbent president has sought re-election.

Confident of his own re-election, Correa, a socialist and proponent of a key role for the state in the economy, has campaigned hard for his allied candidates to the unicameral National Congress - where he is seeking to win a broad majority. He has also worked to bolster his candidates for government offices at the local level.

Recent surveys show Correa with a wide enough edge to meet Ecuador's constitutional standards to avoid a second-round election, even over his closest competitor, former president Lucio Gutierrez (2003-05). Correa would need to either capture a majority of the vote, or a plurality of more than 40 per cent with a margin of at least 10 percentage points over the second-place candidate.

Correa has been polling at 48 to 51 per cent, with Gutierrez no higher than 14 per cent.

Since winning the presidency in the November 2006 election, Correa has won three national votes including a constitutional referendum. The new constitution is the 20th since Ecuador was founded in 1830.

If Correa can finish off his challengers in Sunday's election, he will win a four-year term. Under the new constitution, he would be still be eligible to seek re-election to another four-year mandate.

The president's planned "citizens' revolution" remains unfinished but "credible," according to Santiago Perez, a pollster close to the Correa government.

Political analyst Santiago Nieto of the polling company Informe Confidencial said that the only real threat to Correa is the economy, with the price of oil far below recent receord highs, a significant decline in remittances from Ecuadorian migrants, rising inflation in a dollarized economy, growing unemployment and a government budget deficit of at least 1.5 billion dollars, according to official figures.

Some 38 per cent of the Andean country's 14 million people live below the poverty level.

Euphoria around the election campaign is distracting from the economic problems, but discontent could rise in the months ahead, Nieto said.

Voting itself is expected to take place without incident Sunday, in line with Ecuador's electoral traditions, with observers in attendance from the European Union and the Organization of American States.

The results for the presidential election are expected to be made public Sunday, though broader results are likely to take longer, with 6,000 elected positions at stake.