BRASILIA, June 5 (Xinhua) -- Right-wing candidate Jair Bolsonaro is leading in Brazil's presidential elections in October with 21 to 25 percent of voter support, found a new poll released Tuesday.

Bolsonaro of the right-wing Social Liberal Party is followed by the left-wing former governor of the state of Ceara, Ciro Gomes, with 11 to 12 percent, according to the poll by political news website DataPoder360.

Former environmental minister, Marina Silva, is in third place with 6 to 7 percent of backing, the survey found.

Bolsonaro took the lead after former President Luiz Inacio Lula da Silva, the long-time leading contender in the opinion polls, was jailed on corruption charges.

Lula was sentenced in April to 12 years and one month in jail for corruption and money laundering.

With four months from the elections in October, the Workers' Party (PT) is keeping Lula as its candidate but most analysts believe he will not be on the ballot.

Another name being highlighted as the potential plan B for the PT is former Sao Paulo mayor Fernando Haddad, who has between 6 to 8 percent of voter support.

Two candidates are contending for the nomination of the Brazilian Social Democracy Party, namely the former governor of Sao Paulo, Geraldo Alckmin, and another former mayor of the country's largest city, Joao Doria, both with 6 to 7 percent.

The first round of the presidential race is scheduled for Oct. 7. If no candidate wins 50 percent of the vote, the top two candidates will face off in a second round run-off on Oct. 28.