If the vote were held today, Lula would win the election outright with 53% of the valid votes, avoiding a second-round runoff required if no candidate gets more than 50% of the unspoiled ballots, the pollster said.
If there is a run-off, which would be held on Oct. 30, Lula would be returned to office with 55% of the votes against 35% for Bolsonaro, a 20-point advantage that has been slipping from the 29 points lead he had in December, the poll said.
Lula governed Brazil for two terms in 2003-2010 when the country grew fast due to a commodities super-boom, allowing his administration to raise millions of people from poverty and leave office with record popularity.
A Lula victory would represent an astounding comeback by the 76-year-old former union leader and Workers Party founder who spent 580 days in prison in 2018-2019 on corruption convictions that were later annulled.
Bolsonaro, a populist firebrand, has courted voters by ramping up welfare spending, while pushing to bring down fuel prices, which had been stoking high inflation. His allies in Congress passed a Constitutional amendment allowing his government to exceed spending limits in an election year.
But Datafolha said the effects of the welfare benefits have yet to be felt on the electorate, as increased monthly stipend payments only start in August.
Still, Bolsonaro gained 3 percentage points among low wage earners on less than 2,424 reais ($467) a month, though Lula still holds a wide advantage in this segment at 54% to 23%, Datafolha said.
The poll showed that Bolsonaro’s repeated criticism of Brazil’s voting system, which has raised fears that he might not concede defeat and could try to foster a coup, has not increased his negative rejection numbers, Datafolha said.
Datafolha interviewed 2,556 Brazilians of voting age (16 years) on Wednesday and Thursday. The poll has a margin of error of 2 percentage points up or down.
($1 = 5.1838 reais)
(Reporting by Anthony Boadle and Peter Frontini; editing by Richard Pullin)