Run-Off Likely in Argentina's Presidential Election

Scioli, a moderate Peronist from President Cristina Fernandez's Front for Victory Party, has support from 37.1 percent of those who have decided how they are going to vote, according to the poll published in the daily La Nacion.

His nearest rival Mauricio Macri, the center-right mayor of Buenos Aires city, trails with 26.2 percent, while Sergio Massa, who defected from the ruling party in 2013, has 20.1 percent ahead of the Oct. 25 ballot.

Scioli owes much of his support base to Fernandez loyalists. While he has made new investment a pillar of his campaign platform he has given little away on how far he would unwind state controls in the economy.

That has limited his appeal to voters weary of capital controls, import restrictions, rampant inflation. Some polls show a united opposition would win a second round.

Macri promises swift reforms to open up markets in Latin America's third biggest economy but many voters worry he would return Argentina to the neo-liberal policies of the 1990s that led to a devastating economic depression.

To win outright in the first round a candidate requires 45 percent of valid votes or 40 percent and a 10-point lead over their nearest rival.

"Scioli is near the 40 percent threshold but there is no certainty he will reach it," said Eduardo Fidanza, director of Poliarquia, Reuters reported.

The pollster said that if undecided votes were taken into account Scioli would poll between 38.5 and 41 percent, Macri between 27.5 and 30 percent and Massa 21 to 23.5 percent.

The poll was carried out from Oct. 2-7 and surveyed 1,838 people across the country.