Opinion polls suggest Dilma Rousseff, the president's former chief of staff, will win the election [Reuters]

Brazilians are going to the polls to pick a successor to the hugely popular Luis Inacio Lula da Silva, the country's outgoing president.

Opinion polls suggest that Dilma Rousseff, the candidate from Lula's Workers' Party and the president's former chief of staff, will win Sunday's election, but some observers say that she may need a second round runoff to defeat Jose Serra, her main challenger.

Rousseff, hoping to be the country's first female president, needs more than 50 per cent of the vote to avoid a runoff on October 31. 

Lula has dominated the campaign despite being barred by the constitution from running for a third consecutive term.

Rousseff joined the outgoing president in his hometown of Sao Bernardo do Campo on Sao Paulo's southern outskirts for a large rally on Saturday ahead of the election.

The president enjoys an 80 per cent popularity rating - unprecedented in Brazilian politics - and many voters are prepared to support Rousseff due to his endorsement. For her part, Rousseff has pledged to continue many of her mentor's investor-friendly policies.

Lucia Newman, Al Jazeera's Latin America editor, reporting from Sao Paulo, said that the main change in Brazil after the election was likely to be the gender of the president.

"[Rousseff] is very much the candidate of continuity. She is promising no more, no less, than President Lula's economic, social and foreign policies," she said.

Opinion polls

Two opinion polls released on Saturday indicated that Rousseff would just sneak home in the first round.

Serra, right, has struggled to close on Rousseff and is polling at about 31 per cent [Reuters]

Rousseff had the backing of 51 per cent of those surveyed by pollster Ibope, compared with 31 per cent for former Sao Paulo state governor Serra. A second survey by the Data Folha firm showed her winning 50 per cent, compared with Serra's 31 per cent.

"Candidate Dilma Rousseff has a chance of winning on Sunday as the latest Data Folha poll has shown. This victory is likely to happen with a small advantage, with a margin of two to four percentage points," Ricardo Ismael, a political analyst, said.

"But there is also another possible scenario. Fifteen days ago we were not considering it, but now it is a possible outcome, that there may be a second round."

Serra and Marina Silva, a former environment minister who is running third in the polls, have found themselves unable to get within striking distance of Rousseff in the polls - largely because of Lula's enthusiastic stumping for his candidate.

Lula himself had tears in his eyes on Saturday as he accompanied Rousseff.

"He is very moved because he did so much for us ... He suffered what we suffered," Cleila Santos, a 54-year-old health worker wearing the red of a Lula campaigner, said.

"We sure are going to miss him. He was everything in our lives, and we will never have another president like him," she told AFP.

Programmes initiated by the outgoing leader are credited with lifting 20.5 million people from poverty since 2003, boosting another 29 million into the middle class, and creating new consumers who help drive the economy.

Sunday's polls opened at 8am (11:00 GMT). Voters in the world's fourth most populous democracy are also selecting candidates for congress and state governorships.

The nearly 20,000 candidates in Brazil's 26 states and Federal District are each identified by a number, which campaigners have been drumming into voters' heads for the past few months.

Source: Al Jazeera and agencies