The Ecuadorian presidential race looks set to swing in the Julian Assange's favour meaning he would not be deported to face rape allegation.

An exit poll by Ecuador's Cedatos pollster estimated ruling party leftist Lenin Moreno received some 39.4 percent of valid votes versus around 30.5 percent for conservative ex-banker Guillermo Lasso in Sunday's presidential election.

Lasso was one of two candidates to say on record he would force the Australian to leave Ecuador's London embassy, but early indications suggest he will be beaten by Moreno, who has previously indicated he would back Assange's right to stay.

Whistleblower Julian Assange is set to remain in the Ecuadorian embassy in London

Guillermo Lasso, presidential candidate for the party Creando Oportunidades, CREO, speaks to supporters during a campaign event in Quito, Ecuador

In an interview at campaign headquarters in Ecuador's largest city, Guayaquil, Conservative Guillermo Lasso said that he would ask Assange to leave the embassy within 30 days of winning power.

Assange has been holed up in London since 2012 to avoid extradition to Sweden over rape allegations.

Moreno, a disabled former vice president, needs 40 percent of valid votes and a 10 percentage point difference with his nearest rival to avoid a second round on April 2 and continue a decade of left-wing rule in the Andean country.

Ecuadoreans are choosing Sunday between a candidate who vows to continue President Rafael Correa's populist platform or one of several more conservative contenders who pledge to attack corruption and cut taxes to stimulate the Andean nation's flagging economy.

Polls suggest it will be a tight election, with no candidate likely to garner enough votes to win the first round.

But a third of voters until recently were undecided amid low-energy campaigning as the charismatic Correa prepares to retire from politics.

Correa was among the early voters when polling places opened without incident Sunday morning.

An Ecuador election official carries an electoral kit to be delivered to different polling places by the army, in Quito, Ecuador

The outcome will be watched closely in Latin America, where conservative leaders in Argentina, Brazil and Peru have assumed power in the past 18 months after the end of a commodities boom that boosted leftists like Correa.

Outside the region, much of the interest in the election focuses on what the outcome will mean for WikiLeaks founder Julian Assange and his ability to remain at the Ecuadorean embassy in London.

Julian Assange - founder of Wikileaks

Ruling party candidate Lenin Moreno, who is Correa's hand-picked successor, has indicated he would back Assange's continued stay.

But his main challenger, former banker Guillermo Lasso, has indicated in interviews that he would evict the Australian activist within 30 days of taking office.

The contest puts Correa's legacy on the line as well.

The self-declared 21st century socialist who took office in 2007 ushered in a period of stability after a severe economic crisis that saw three presidents toppled in protests and the adoption of the U.S. dollar to control rampant inflation.

While Correa has been praised for reducing inequality and overhauling the nation's infrastructure, polls show a majority of Ecuadoreans favor change.

Formerly flush government budgets have been slashed and thousands of people at state-run companies laid off as oil revenues in the OPEC nation declines. The International Monetary Fund expects Ecuador's economy to shrink 2.7 percent this year, and analysts predict that the next president will have to seek a bailout from the Washington-based lender to help with financial problems made worse by last year's 7.8 magnitude earthquake.

Moreno has pressed voters to uphold the president's 'Citizens' Revolution,' while his challengers vow to eliminate taxes they contend hampers growth and strengthen democratic institutions they say were weakened by Correa's leadership.

Recent polls show Moreno winning 28-32 percent of the votes.

He is trailed by Lasso, who lost to Correa in 2013 and is polling with 22 percent. Also seeking the presidency is Cynthia Viteri, a conservative ex-congresswoman, and Paco Moncayo, the former mayor of the capital Quito.

Lourdes Vasquez who is disabled, casts her vote ahead of Sunday's election, from her house in Quito, Ecuador

To avoid an April runoff, a candidate must clench 50 percent or more of all votes, or 40 percent with a 10-point lead over the closest rival.

In the final weeks before the election, corruption allegations involving Moreno's running mate, current Vice President Jorge Glas, have dominated airwaves.

A leaked video widely shared on social media shows a disgraced former cabinet minister undergoing a lie detector test and accusing Glas of taking some of the $12 million in bribes paid to state-run PetroEcuador for construction of a refinery.

Glas has denied any wrongdoing.

As Ecuadoreans prepared to vote, the candidates offered contrasting visions for the country of nearly 16 million.

'We have two options,' Lasso told voters on Twitter. 'More of the same or change.'

Moreno, who has used a wheelchair since being shot in an assault in 1998, told voters that Ecuador doesn't need drastic changes, just a 'push.'

'Don't abandon the revolution,' he has repeated during the final campaign stretch.