Brazil's president, engulfed in a growing corruption scandal, faces another month of campaigning to win a second term after results from Sunday's polls forced him into a runoff with his chief rival.

Luiz Inacio Lula da Silva needed a simple majority of votes to avoid a runoff on Oct. 29, but fell short with 48.8 per cent of the vote, compared with 41.4 per cent for centre-right candidate Geraldo Alckmin, with 98 per cent of the ballots counted, Brazilian election authorities said Sunday evening.

President Luiz Inacio Lula da Silva makes an 'L' sign for victory after voting in Brazil's general election on Sunday.
(Marcelo Hernandez/Associated Press)

The result was a devastating blow for the former radical union leader, who was favoured to win due to the economic stability and anti-poverty programs he brought to Brazil. Earlier in the week, Silva's support had reached 59 per cent.

His campaign manager, Marco Aurelio Garcia, said Sunday the president and his campaign staff "always prepared ourselves for a two-round election."

Allegations plagued campaign

The scandal that has enveloped Silva's administration erupted only weeks before the presidential election.

Six members of Silva's Workers Party, including an old friend who ran his personal security detail, face arrest warrants for their roles in an alleged effort to buy damaging information about Silva's political opponents. Silva fired his campaign manager days before the election.

Newspapers ran front-page photos Sunday of piles of money allegedly used to buy the information. Local media reported the photos were leaked by federal police.

But many Brazilians seem willing to overlook the corruption allegations because they feel their lives have gotten better during Silva's four years in office. He has brought a stable economy and social programs that have lifted millions out of poverty.

Alckmin promised "ethics will defeat corruption" when he voted Sunday in the upscale Morumbi district.

Silva also voted Sunday morning in the working-class city of Sao Bernardo de Campo on the outskirts of Sao Paulo where he got his start as a labour leader.

"This is a glorious moment for Brazil because the election consolidates the democratic process," he said after voting.

Support in poorest areas

Silva made a much-criticized decision to skip the nationally televised presidential debate on Thursday.

Still, his efforts to reduce poverty play well in the slums of Sao Paulo and Rio de Janeiro.

"Zero Hunger," his expanded food stamp-like program, guarantees about $30 a month to virtually all poor families, provided they vaccinate their children and keep them in school. It distributes $325 million a month to 45 million of Brazil's 187 million citizens.

The program has helped millions of Brazilians out of poverty, studies show.

A poor farmer's son who became a fiery union leader and was later elected as Brazil's first leftist president, Silva surprised many by governing as a moderate once taking office. His deft handling of the economy won him backing on Wall Street and in Brazil's shantytowns.

His second-term priorities include reforming the tax and labour rules.

More than 125 million Brazilians were expected to vote for the president, governors for all 26 states and the federal district, all 513 federal deputies of the lower house and 27 of the 81 Senate seats.

Voting is mandatory in Brazil, and those who fail to justify their absence both within Brazil and abroad may be fined.

With files from the Associated Press